Project report 2

B.Sc. Honours Food Science and Nutrition Letterkenny Institute of Technology

THE EFFECT OF SOURDOUGH ON GLUTEN FREE BREAD Kerri Pope

Project submitted in partial fulfilment for the award of a B.Sc. (Hons) in Food Science & Nutrition by Letterkenny Institute of Technology

Contents Acknowledgements.................................................................................................................iii Abstract....................................................................................................................................iv 1.0 Introduction........................................................................................................................6 1.1.1 Types of sourdough......................................................................................................8 1.1.2 Preparing Sourdough..................................................................................................9 1.2.1 Flour........................................................................................................................10 1.2.2 Water.......................................................................................................................10 1.2.3 Salt...........................................................................................................................10 1.2.4 Sugar.......................................................................................................................11 1.3 Stages of sourdough production......................................................................................11 1.3.1 Dough stage................................................................................................................11 1.3.2 Bacterial Growth.......................................................................................................11 1.4 Lactic acid bacteria in sourdough...................................................................................11 1.4.1 Homo-fermentative and Hetero-fermentative lactic acid bacteria.......................12 1.4.2 Types of lactic acid bacteria in Sourdough.............................................................13 1.4.3 Yeast............................................................................................................................14 1.5 Gluten................................................................................................................................15 1.5.1 The role of gluten in Coeliac Disease.......................................................................15 1.6 Cereals...............................................................................................................................17 1.6.1 Wheat..........................................................................................................................17 1.6.2 Wheat Flour...............................................................................................................18 1.6.3 Rice..............................................................................................................................18 1.6.4 Rice Flour...................................................................................................................18 1.7 Psuedocereals....................................................................................................................19 1.7.1 Quinoa........................................................................................................................20 1.7.2 Quinoa Flour..............................................................................................................20 1

1.8 Fermented Foods..............................................................................................................21 1.8.1 Fermentation of Cereals............................................................................................21 1.9 Bread Making and Methods............................................................................................21 1.9.1 Straight dough Method.........................................................................................22 1.9.2 Sponge Method.......................................................................................................22 1.9.3 Chorleywood Method............................................................................................22 1.10 Process variables............................................................................................................23 1.10.1 Dough Yield..............................................................................................................23 1.10.2 Temperature.............................................................................................................23 1.10.3 Starter Culture.........................................................................................................23 1.11 Sensory Analysis.............................................................................................................24 2.0 Materials and methods:...................................................................................................26 2.1 Ingredients for Bread...................................................................................................26 2.2 Sensory Evaluation...........................................................................................................27 2.3 Physical attributes testing: Characteristics of Bread....................................................27 2.3.1 Volume and density....................................................................................................27 2.3.2 Colour:........................................................................................................................27 2.3.3 Moisture Content.......................................................................................................27 2.3.4 Texture........................................................................................................................28 2.4 Microbiological Testing....................................................................................................28 2.4.1 Production of a Growth curve for Sourdough Starter Culture.............................28 3.0 Results...............................................................................................................................29 3.1 Sensory Analysis results...............................................................................................29 3.1.1 Results of preference sensory testing by LYIT students.....................................29 3.1.2 Descriptive analysis................................................................................................34 3.2 Physical Attribute Testing: Characteristics of Bread................................................34 3.2.1 - Volume and Density.............................................................................................35 2

3.2.2 Texture Analysis of Bread samples.......................................................................36 3.2.3 Colour analysis of Bread samples.........................................................................37 3.2.4 Moisture Content Determination.........................................................................39 3.3 Microbiological Testing of Samples.............................................................................40 4.0 Discussion..........................................................................................................................41 5.0 Conclusion.........................................................................................................................48 6.0 References.........................................................................................................................50 7.0 Appendices........................................................................................................................56 Appendices 1 - Standard Questionnaire...........................................................................56 Appendices 2 - Coeliac Questionnaire..............................................................................58 Appendices 3 – Physical Risk Assessment........................................................................60 Appendices 4: Project Plan................................................................................................62

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Acknowledgements

First I would like to thank my supervisor Mary Carr for all her help and guidance throughout this year.

Also I extend my thanks to Mr. Brian Carney project supervisor for all his help. Thank you to all the students who helped with my sensory analysis. Thank you to the lab technicians Ken McIntyre and Brendan Alexander for their help with the practical work Finally a big thank you to my family and friends without whom the past four years would not have been possible.

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Abstract

Over the past number of years there has been a rapid increase in the occurrence of coeliac disease and also a rise in the number of people who consume gluten free products, and there does not appear to be any stopping this rapid trend. With this the number of gluten free products on the shelfs has risen dramatically. Much of these products are considered distant from the gluten varieties and can be lacking nutritionally. Even with the many advances in food technology people are still dissatisfied with the quality of gluten free products.

This project analyses the quality of gluten free bread when prepared using an ancient sourdough technique. By looking at the physical characteristics, organoleptic properties, and microbiological quality the aim is to determine if sourdough bread would be a satisfactory substitute for gluten bread products in relation to both taste and nutritional benefits.

Sensory analysis forms the backbone of this experimental analysis and the students qualitative and quantitative results are used in conjunction with all other results to determine if in the case of sourdough bread gluten free varieties are deemed acceptable.

Although it was sourdough containing gluten that did fair best in the sensory analysis, much of the information found here could be used in further research in the customers expectation of gluten free bread products.

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Chapter 1- Literature Review 1.0 Introduction Many people are becoming both aware and concerned with the different ingredients used in food and how these affect the digestive system. As a result of this food scientists have been working practically to develop new and alternative food products which the consumer will find fulfils their requirements. Much of this research has led to additives often chemical being added to foods in order to extend shelf life, improve taste or to limit calories as well as other functions. These developments in processing have not only been for improvement of the quality of the food product but also for improving the safety of the product, in particular for those who have an intolerance or allergy to different constituents of a food.

Bread has been produced for thousands of years. Over this time the process of producing bread has advanced and there are now a huge array of different bread types on the market.

This wide variety of breads has developed in response to the changing needs of the population and as the scientific knowledge of the fermentation process has improved.

Ingredients have been added and removed to improve the functions of the bread. At times by doing this companies are sacrificing the organoleptic properties which has made bread a staple food in most of the world. The production of bread began with the harvesting of cereals which began in primitive times. (Coda et al. 2014) Cereals grew throughout the world and due to the nature of the plant “dropping seeds� they required little maintenance. This made them an ideal food source for the people at that time who had little tools or botanic knowledge.

As the population increased the demand for wheat increased. This led to an increase in production of wheats and chemical changes in the wheat itself. By increased use of fertilizers containing nitrogen the protein (gluten) content of the wheat has increased.(CropNation 2012) Some believe that it is this increase which has led to the increase of the incidence of gluten intolerance or allergies. A person afflicted with a gluten intolerance may experience gastrointestinal discomfort when gluten is being digested.(Case 2005) This increase has resulted in the mass production of gluten free products. Insert statistics about gluten free products.

Today wheat is the most prominent of the cereals in the world except in third world or developing countries where gluten-free cereals such as rice or iburu are more common.

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Psuedocereals are a group of plants which have much in common with cereals but are different structural properties. Quinoa is one of these psuedocereals and it is also gluten free.

Due to the increase in international trade in the industrial age these alternative cereals and psuedocereals are gaining popularity in the developed world. Through international trade every generation appears to be exposed to a food that the previous generation has not encountered. Also the digital age has brought with it the internet which has given people more access to the contents of their food and the effect that these have. This has led to much of the population choosing products which have gone back to traditional methods and are additive free.

Originally fermentation of cereals into bread was a spontaneous process neither the process nor the microorganisms responsible were understood. Nevertheless a nutritious and fulfilling food was being developed. Sourdough was being produced at this time. Sourdough is a bread product that is a combination of flour and water which has been fermented with naturally occurring lactic acid bacteria (LAB) (Poutanen and Katina 2014) Today with the extensive knowledge of both the process and the organisms new applications for sourdough technology are being considered.

While many products are available today for those with a gluten allergy or intolerance much research is still being conducted. One of the main concerns for those bakeries developing a gluten free product is that it is one of the functions of gluten is to increase the shelf life and that this is hard to achieve using gluten free flours. Consumer research on the current products has found that many people consider gluten free products to be undesirable and too unlike products containing gluten.

This review investigates the current research available on sourdough technology and gluten free cereals and psuedocereals to find if a primitive approach can be used to solve a modern problem. The use of sourdough technology may indeed be a way of producing a “clean label� bread safe for consumption by the entire population.

1.1 Sourdough Sourdough is a type of bread which is prepared using a sample of dough fermented by lactic acid bacteria as a leavening agent. (Poutanen and Katina 2014). This is a very traditional method of leavening in bread making.(Gänzle 2014).The production of sourdough can be 7

traced back to ancient times. It is because of their superior quality and the prolonged shelf life that sourdoughs have maintained their importance. The consumption of sourdough contributes to the gastronomy of many countries at the present time (De Vuyst and Neysens 2005).

1.1.1 Types of sourdough There are three types of sourdough production (types I, II, and III) Type I sourdough is a sourdough which is restarted using a part of the previous fermentation.

This is the most traditional method of sourdough production. Type I sourdoughs do not require yeast (Rupesh S. Chavan, Chavan, Shraddha R. 2015). With Type I sourdough production daily refreshments are required to keep the organisms active. This method used for the production of one of the most famous sourdoughs – San Francisco sourdough. It is an example of a pure culture sourdough containing Lactobacillus sanfranciscensis which is resistant to microbial contamination (De Vuyst and Neysens 2005).

Type II sourdough uses to the back slopping or inoculum enrichment technique used in the production of sourdough bread. It is a conscious method for selecting the more adaptable starter strains to shorten the fermentation process and to reduce the risk of failure (Coda et al., 2014). It is common for home baking that the sourdough is enriched daily. For industrial bread making it is common place to for back-slopping of sourdough to occur less frequently weekly or even monthly. If this is the case then additional starter cultures must be used (Coda et al., 2014) This method requires the addition of yeast (Rupesh S. Chavan, Chavan, Shraddha R. 2015). When the inoculum is enriched the microflora of spontaneous fermentations may be found including homo-fermentative and hetero-fermentative lactobacilli (De Vuyst and Neysens 2005). Type II sourdoughs require yeast as a leavening agent (De Vuyst et al. 2014).

Type III sourdoughs are the most convenient method of sourdough production on industrial scale productions (Rupesh S. Chavan, Chavan, Shraddha R. 2015). They require faster acidification without damage to the sensory characteristics. These are dried sourdoughs commonly prepared with LAB which is resistant to drying like Lactobacillus brevis or Lactobacillus plantarum (De Vuyst and Neysens 2005). The drying process means that this sourdough has an increased shelf life. Type III sourdoughs can be prepared in bulk and allows for a standardised end product for mass production (Wick et al. 2015). For home sourdough

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production this method is not suitable. Similar to type II sourdoughs type III require yeast for leavening (De Vuyst et al. 2014).

1.1.2 Preparing Sourdough Sourdough has two main processes that differentiates it from a standard shape dough method.

The main difference is the presence of lactic acid bacteria, the second is the fermentation time which can vary from 8h to over 144hrs (Gänzle 2014).

Sourdough is a combination of flour and water which is fermented by lactic acid bacteria (LAB) (Poutanen and Katina 2014). Sourdough gets its name from the fact that both the dough and the bread are acidic (McGee 2004). The sourdough is an intermediate product that contains metabolically active yeast and LAB strains (De Vuyst and Neysens 2005). While the LAB are active they produce metabolites and activate a cascade of endogenous enzyme activities that modify the constituents of the grain (Poutanen and Katina 2014). It is the waste products of acetic acid and/or lactic acid in the mix that gives the sour taste to the end product (De Vuyst and Neysens 2005).

Sourdough is increasingly being used to improve both the technical and nutritional quality of baked goods. The use of sourdough also increases the safety of cereal based products by making gluten products easier to digest for coeliacs (Poutanen and Katina 2014). The use of sourdough can also improve the safety of a product by competitive inhibition meaning that pathogens will not be able to flourish as the nutrients are being used up by the starter culture.

(Jay and Loessner 2015) The use of sourdough is based upon an earlier natural or spontaneous process (Rupesh S. Chavan, Chavan, Shraddha R. 2015) were discarded cereals would natural ferment but was not understood. Benefits of sourdough are extended shelf life, quicker volume gain, postponed staling, better flavour, and improved nutritional value (Rupesh S. Chavan, Chavan, Shraddha R. 2015). The use of sourdough also improves the sensory characteristics of the bread including volume, even baking, colour, taste, texture and aroma (Rupesh S. Chavan, Chavan, Shraddha R. 2015). These effects are dependent on the bioconversion of the flour components in the dough stage (Gänzle 2014). During sourdough production the mouthfeel and palatability of wholemeal bread can be improved without removing important nutrition components (Chavan 2015).

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1.2 Ingredients in sourdough

1.2.1 Flour Flour is the most important ingredient in bread making

(Rupesh S. Chavan, Chavan,

Shraddha R. 2015). Flour is important as it modulates the specific characteristics of the baked products. Wheat flour is the most common flour used. Other flours such as rice, quinoa, spelt, garbanzo can be used for gluten free baking (McGee 2004). The enzymes in the flour provide substrates for bacterial growth in sourdough production (Gänzle 2014). The starch in the flour will provide the fermentable sugars for LAB metabolism. During sourdough production flour will function as the feed and contains all the nutrients required for the microflora to flourish.

1.2.2 Water Water may be the most simple of the ingredients found in sourdough but it has very important properties which have a vital role in the baking, final product quality, and the shelf life. It works as a solute for the other ingredients and functions in dispersing them evenly throughout the mixture (Pyler and Gorton 2008). The quality of the water is also important. During feeding of the sourdough starter culture it is important that the water be pure as some metals may interfere with the growth of the organisms.

1.2.3 Salt The importance of salt in bread should not be depreciated. Salt performs more than just flavour improvement. Salt controls the action of the yeast in bread and in sourdough has the same effect on the LAB. Too little salt will result in a bread that is difficult to work with due to an increased rate of fermentation. If too much salt is used then the nutrients that contain water may leave the yeast cells through osmosis (Stear 1990). If too much salt is added it may kill off the organisms meaning the bread does not have a chance to ferment. The salt also has 10

an effect on the physical appearance by bleaching. (McGee 2004) Salt controls the action of the yeast and therefore controls the volume of the bread. Salt is only added in small quantities. It favours the action of the amylases and maintains a supply of maltose as a food for the yeast and LAB (Chavan 2015). Salt should never be added to the starter as it will destroy the culture.

1.2.4 Sugar Sugar can be added to sourdough but it is not necessary. The flour used has all the sugars that the LAB need to metabolise. Sugar can be added to the surface of the bread before it is baked to give extra colour. If a sweeter sourdough is required then sugar may be added when the dough is being mixed not at the starter stage.

1.3 Stages of sourdough production 1.3.1 Dough stage During the dough phase the starch is being broken down into fermentable sugars which then become available for the Lactic acid bacteria (LAB) and yeast metabolism (Gänzle 2014)

1.3.2 Bacterial Growth Phase I is the induction or lag phase, during this time the microorganisms are adjusting to the substrate and are absorbing the nutrients for their metabolism. Through this absorption the cells are increasing in size but there is no multiplication. (Byrd and Powledge 2006) The time this takes is inversely relative to the cell count present in the starter culture. The less cells present then the longer the induction phase will take. An average for this phase is 2 hours (Stear 1990). Phase II is the acceleration or exponential growth phase during which the organisms have adapted to their environment and exponential growth can occur. Cells are now multiplying, the more cells that are created then the faster this process gets. This exponential growth phase can be maintained by providing the organisms with a steady supply of nutrients (Byrd and Powledge 2006). In sourdough this process is known as feeding (McGee 2004). After feeding has concluded the organisms enter phase III, the stationary phase. The growth and death rate are equivalent to each other. The bacteria die off as the nutrients are running out or because the waste products are building up to a lethal level (Byrd and Powledge 2006). After this, stage IV or the death phase begins, the availability of

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nutrients has been reduced so that cells can no longer thrive and cell autolysis occurs (Stear 1990).

1.4 Lactic acid bacteria in sourdough The bacteria found in raw cereal grains are mesophilic and are commonly found in spontaneously fermented sourdoughs. They can be gram negative aerobes, facultative anaerobes gram positive LAB homo-fermentative rods, Hetero-fermentative rods and homofermentative cocci. Undesirable Bacillus cereus and Staphylococcus aureus and other bacteria may be present in the raw cereals and psuedocereals (De Vuyst and Neysens 2005).

Lactic acid bacteria (LAB) have been shown to improve both the sensory and baking qualities of the final product. The use of LAB also offers the opportunity to increase the energy density and to decrease anti-nutritional constituents such as tannins and phytic acid (Coda et al.

2014).

Phytic Acid is a storage form of phosphorous in grains which binds many minerals such as Ca, Fe, K, Mg, Mn, and Zn. The presence of phytic acid in gluten free bread products means that these minerals will not be available to be absorbed by the consumer possible leading to mineral deficiencies (Arendt et al. 2011). The acidification brought on by the fermentation activates cereal phytases making these nutrients available (De Vuyst and Neysens 2005).

1.4.1 Homo-fermentative and Hetero-fermentative lactic acid bacteria LAB can be divided into two categories homo-fermentative and hetero-fermentative (Rupesh S. Chavan, Chavan, Shraddha R. 2015). Homofermentative LAB catabolize one mole of glucose into CO2, lactate and ethanol. While heterofermentative LAB also produce acetic acid. The acetic acid by product is important as they provide characteristic tastes and aromas to the food they ferment.(Todar 2010) Homo-fermentative LAB include LAB from the species Lactobacillus, Lactococcus, Enterococcus, Streptococcus and Pediococcus (Kenneth Todar 2015). Homofermentative LAB convert sugars to Lactic acid exclusively (Borch et al. 2015) and at a quantity of around 90% conversion to lactic acid (Stear 1990). Hetero-fermentative LAB produce lactic acid at a quantity of 50% from sugar but also produce ethanol, acetic acid and other organic acids.

(Stear 1990).Acetic acid accounts for around 20% of the total acidity of sourdough (Jay and 12

Loessner 2015). Testing for CO2 production in a nutrient broth or agar is a simple method used to distinguish between the two types of fermenters (Borch et al. 2015). Lactobacilli can only develop in a carbohydrate containing media which has been enriched with trace elements so this must be prepared when performing a qualitative analysis (Stear 1990).

The majority of fermented foods depend on homo-fermentative LAB strains for the desired properties. However most sourdoughs are dependent on hetero-fermentative LAB especially when they are prepared traditionally (De Vuyst and Neysens 2005). Each category of LAB produces different flavour compounds in the bread. Organic acids which are not volatile are produced by homo-fermentative LAB. Organic acids function to decrease the pH and give aroma to the bread. Hetero-fermentative LAB produce organic acids including alcohols, ketones and aldehydes. In order to generate sufficient amounts of these requires a fermentation time of 12-24hours (Rupesh S. Chavan, Chavan, Shraddha R. 2015) A commercially available sourdough starter is commonly composed of mixtures of different LAB groups that will ensure good acidification and aromatization (Chavan, 2015).

LAB can also produce enzymes which can reduce the toxicity of wheat and rye flours over a long fermentation period (Arendt et al. 2011). In the production of bread using gluten free flours LAB can degrade contaminants and also improve the nutritional qualities (Arendt et al.

2011). The hydrolysis of protein during the fermentation is of vital importance for the quality of the bread. The use of LAB for sourdough fermentation gives an increase in the amounts of amino acids present (Rollรกn et al. 2010). A study has shown that prolonged fermentation of dough by LAB could decrease the risk of rye becoming contaminated with toxins in gluten free products intended for consumption by coeliac patients (Rollรกn et al. 2010).

1.4.2 Types of lactic acid bacteria in Sourdough Microbiological studies have shown more than 50 species of LAB in sourdough cultures (De Vuyst and Neysens 2005). The type of LAB present in sourdough determines the characteristics of the bread in terms of aroma, leavening properties and aroma (Arendt et al.

2011) In type I and type II sourdoughs the microflora present in the sourdoughs will vary from one producer to another and even from just one loaf to another in terms of both quality and quantity (Stear 1990).

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The most common genera of LAB that have been isolated from sourdough starter cultures are Lactobacillus, Leuconstoc, Pedicoccud and Weisella, with Lactobacillus being the most common (Rollรกn et al. 2010). The lactobacilli in the dough produce mainly acids and aromatic substances (Stear 1990). Lactococci, Enterococci and Streptococci are rarely found (De Vuyst and Neysens 2005).

It is common to find faculatively and obligatory hetero-fermentative lactobacilli such as Lactobacillus

plantarum,

Lactobacillus

alimentarius,

Lactobacillus

sanfrancensis,

Lactobacillus pontis, Lactobacillus brevis, and Lactobacillus reuteri in sourdough breads (Coda et al., 2014) The dominance of the obligate hetero-fermentative is explained mainly by their competiveness and adaption to the environment in the sourdough (De Vuyst and Neysens 2005). Their carbohydrate metabolism is highly adapted to fermentable sugars found in dough maltose and fructose (De Vuyst and Neysens 2005). The utilization of these sugars gives a higher energy yield than with that encountered with homo-fermentative strains (De Vuyst and Neysens 2005).

The biodiversity of the LAB found in sourdough can be thought of as restricted or diverse. It must be recognised that an increasing number of strains of LAB are unique to sourdough.

Opportunistic strains sometimes occur they may aid in the fermentation or may be considered contaminants (De Vuyst and Neysens 2005) The sourdough lactobacilli have several high stress response mechanisms to overcome the changes in pH, temperature, available water, oxidation, and energy source (De Vuyst and Neysens 2005).

1.4.3 Yeast The LAB to Yeast ratio in sourdough is generally 100:1 (De Vuyst and Neysens 2005). Some species of yeast have been found in raw cereals including Candida, Cryptococcus, Pichia, Rhodotorula, Torulaspora, Trichosporon, Saccharomyces, and Sporobolomyces. Estimated quantities of yeast are 2x103CFU/g (De Vuyst and Neysens 2005). More than 20 species of yeast have been isolated from sourdough including Candida and Saccharomyces (De Vuyst and Neysens 2005).

Saccharomyces Cerevisiae is the most common yeast used in sourdough. The function of the yeast is to metabolize the glucose, fructose and sucrose. These sugars are known as the fermentable sugars (Chavan, 2015). Maltose is also present but is not metabolized by yeast.

The amount of glucose present increases during fermentation and sucrose decreases, this is 14

due to the presence of invertase. Yeast works under anaerobic conditions producing CO 2 which is a leavening agent and enhances the volume of the bread (Chavan, 2015). Later during bread production sugars are released and are used

by enzymes to produce gas

(Rupesh S. Chavan, Chavan, Shraddha R. 2015). Saccharomyces Cerevisiae is not found in raw materials but instead is commonly added as baker’s yeast in daily bakery practices (Rollán et al. 2010).The use of yeast without LAB has shown to result in a decrease in amino acid concentration (Rollán et al. 2010).

The yeasts in sourdough produce carbon dioxide which is essential for aeration, bread volume and crumb structure (Stear 1990). By producing carbon dioxide in the mixture the yeast creates the conditions which are favourable to the facultative anaerobic Lactobacilli (Stear 1990).

1.5 Gluten Gluten is an insoluble, complex mixture of proteins called glutenins and prolamins and other ingredients (SafeFood 2010). Wheat flour contains two proteins- Gliadin and Glutenin. When they are formed into a mixture gluten is formed which gives an elastic and cohesive network.

The presence of gluten is what gives wheat breads their functional properties (Chavan 2015).

Contributing to the water absorption capacity, viscosity and the elasticity of the dough (Arendt et al. 2011). These proteins are also present in rye, barley, a cross between wheat and rye called triticale and possibly oats. Dry flour does not contain gluten, gluten is only formed when four is mixed with water (Figoni 2010).

1.5.1 The role of gluten in Coeliac Disease There are two dietary issues associated with wheat these are wheat allergies and the more serious gluten intolerance or Coeliac disease (SafeFood 2012).Coeliac disease (CD) is an immune mediated disease which is triggered in genetically susceptible individuals when they eat gluten from wheat, rye, barley, and other closely related cereal grains (Arendt et al. 2011).

It is during gastrointestinal digestion and the release of Proline and Glutamine that a T-cell mediated response occurs which is associated with CD (Arendt et al. 2011). During digestion the prolamins in gluten cause an inflammation of the small intestine. By damaging the villi of the small intestine that are responsible for absorption of minerals these attacks reduce the absorption of nutrients, minerals and fat soluble vitamins.(Foundation 2001) Chronic exposure to gluten by a coeliac carries a risk of osteoporosis and intestinal cancer (SafeFood 15

2010). This is of major concern as it is thought that 2.5million Americans are undiagnosed.

(Foundation 2001) This is not the only concern a study has shown that the later in life that coeliac disease is diagnosed then the higher the risk the person will be diagnosed with another autoimmune disorder.(Biagi et al. 2002) Presently medical nutrition therapy (MNT) with nutritional care is the only accepted treatment for coeliacs which involves complete elimination of gluten from the diet. (Arendt et al. 2011). Removing all gluten products from the diet is not easy. In recent years there has been an increase in the amount of “gluten free products� on the market. The manufacture of totally gluten-free food is difficult and as a result, a marketing review has found that gluten free products are thought of as lower quality, with poor mouth feel and having off flavours (Arendt et al. 2011) and are often expensive. They may be labelled 'gluten-free' if the gluten content does not exceed 20 mg/kg in the food as sold to the final consumer. Removal of gluten from the diet is a part of life for around 10 people out of every 1000 in Ireland.

(SafeFood 2010) As a large number of CD patients also exhibit lactose intolerance particularly shortly after diagnosis it is preferable that lactose powder is not present in gluten free products (Arendt et al. 2011). The use of sourdough technology is thought to hydrolyse the proline rich allergenic fragments (RollĂĄn et al. 2010). This could make gluten containing cereals safe for consumption by those with coeliac disease.

In recent years there has been a rise in coeliac disease in the population. This could be for one of a few reasons. It is possible that gluten intolerance is being misdiagnosed as an allergy. It is also conceivable that people are diagnosing themselves but there is another underlying health problem. Current research may indicate that the amount of gluten present in wheat is on the rise and exceeding the tolerance level of much of the population. Studies have shown that the amounts of nitrogen used in the fertilizers are responsible for this increase. The concentration of nitrogen in fertilizer is being increased as in some areas of the world including the US market specifications state that protein must be over 13%. For wheats intended for baking bread this quantity of protein will require 200kg of nitrogen per hectare of wheat crop (CropNation 2012).

There has also been an increase of people who have not been diagnosed with coeliac disease abstaining from consuming gluten. There have been a number of studies conducted in order to determine the effect that gluten has on people who are not diagnosed with coeliac disease.

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Results from these studies may indicate that abstaining from gluten would be effective for people with other digestive issues besides coeliac disease. In one of these studies, 34 people with irritable bowel syndrome were randomized to either a gluten containing or a gluten free diet. The group of people who were consuming gluten reported more pain, bloating, stool inconsistency and fatigue when compared with the gluten free subjects (Biesiekierski et al.

2011). There is still much research to be done in this area and today there is no conclusive scientific evidence to prove that there is harmful effects associated with gluten consumption for people who are not gluten intolerant.

1.6 Cereals Cereals are defined as plants of the grass family which produce grains (McGee 2004).

Farming of cereals dates back to 7000 B.C. for wheat and barley, 4500 B.C. for millet and sorghum, 400 B.C. for rye and 100 B.C. for oat (Coda et al. 2014).Triticale is the only cereal of our time as it was first cultivated in the 1930’s. (McGee 2004) Cereals were the first and most important foods for primitive humans. It is believed that cereals were first consumed raw and then in time they were ground with primitive objects to yield whole or semi refined flours that were then watered down and made into a nutritious gruel (Serna-Saldivar 2010).

One advantage of cereals is that they can grow in those areas which are too dry for the growth of trees bearing fruit. They will live or die in a season or two and it is generally by the sheer numbers of the crops that they guarantee that some offspring will survive for the following season. This is opposed to the chemical means of ensuring offspring utilized when growing other plants. (McGee 2004)

1.6.1 Wheat While many cereals are cultivated the most popular is wheat which accounts for 50% of the world’s cereal production. (Coda et al. 2014) In Ireland 545,000 tonnes of wheat were produced in 2013 alone (Fao 2015). In 1961 this Figure was 469,900 tonnes so the demand has always been high. Wheat is the product of three different grains. Research has indicated that the cross pollination happened around 10,000 B.C (allaboutwheat 2011). It is said that einkorn which was a diploid species was cross pollinated with wild goat grass (Aegilops speltoides) another diploid species giving us two tetraploid species – Emmer and Durum.

Then 2,000 years later this tetraploid species again combined with Aegilops speltoides giving us the wheat we use in bread production today: Triticum aesivum (McGee 2004).Twenty 17

percent of global calories are thought come from wheat (Monsanto 2014). Wheat is the most diverse cereal and it is present in the most cereal products. It is the only cereal that has functional gluten. Wheat is available in three different types each with different functions.

These are hard wheat, soft wheat, and the oldest type durum wheat. Hard and soft wheat are mainly ground up and used for bakery products whereas durum wheats most common use is in the production of semolina. (Serna-Saldivar 2010)

1.6.2 Wheat Flour Flours that come from the hard/strong wheat are normally used in breads which require a strong gluten network. Soft wheat would be used for savoury cakes or pastries were a strong gluten network would be undesirable. (Marti et al. 2015) Most of the bran and wheat germ are present in hard wheat flour. (Bushuk and Rasper 1994) Of all the cereal flours available wheat is the only one that will form a three dimensional viscoelastic dough when it is mixed with water (Song and Zheng 2007) Since gluten is present wheat flours are not suitable for those sensitive to gluten.

1.6.3 Rice Although a large amount of wheat is produced it is not generally found in poorer countries.

Grains such as rice, iburu, black fonio or millet constitute the staple diet for human consumption in these countries. This knowledge has led to an increased awareness in these ethnic and ancient grains for bread production. (Coda et al. 2014) As well as being of interest to third world countries these grains are also of interest because of their highly nutritional nature and special dietary uses. Check wording here.

1.6.4 Rice Flour Rice flour is available in three varieties: flour ground from ordinary short grain rice called joshinko, and two flours made from glutinous rice called mochiko and shiratakmako (Tsuji 2012). All varieties of rice flour are gluten free making it safe for consumption by coeliacs and those concerned with gluten consumption. Glutinous rice flour has a sweet flavour and therefore it is most commonly used for desserts such as wagashi (Gordenker 2015). Joshinko is the most common rice used for savoury dishes such as rice noodles and baked products such as bread. One benefit of rice flour is that it is available cheap and can also be easily made at home with little investment in equipment (Instructables 2015). Rice flour is 18

noteworthy for being around 90% starch and also for having the smallest starch granules of all the major cereals being around a quarter a size of wheats granules. (McGee 2004) Protein in cereals contribute to the water holding capacity and as rice flour has less proteins this means that it absorbs relatively little water. (Williams et al. 2000) As rice flour is gluten free its ability to produce raised breads is limited. In order to be used in bread production rice flour is often used along with xanthan gum or a similar long chain carbohydrate which will function to hold the dough and to retain gas bubbles (McGee 2004). Xanthan gum is produced by Xanthomonas campestris in an industrial fermentation process. This is cleansed by the fermenting organisms and provides elasticity like the wheat proteins would do. The presence of anionic side chains on the xanthan gum molecules encourages water absorption and makes xanthan gum soluble in cold water (Cargill 2015). There is also research being conducted in the use of chia and flax instead of xanthan gum. These seeds have advantages over xanthan gum as they contain not only protein but also fibre which can be lacking the diet of a coeliac patient. They are also rich in omega-3 fatty acids (Gelski 2014).The consumption of Omega-3 fatty acids have been shown to lower levels of depression, lower inflammation of asthma, reduce ADHD symptoms, and protect against Alzheimer’s disease and dementia. It has also been shown to be important during pregnancy and it aids with visual and neurological developments.(Teale et al. 2006)

1.7 Psuedocereals Psuedocereals do not belong to either the grass family nor are they true cereal grains. These are evolutionary distant from these but they do still produce grains (Coda et al. 2014). These psuedocereals include quinoa, amaranth and buckwheat. A characteristic feature of psuedocereals is that they are dicots whereas cereals are classified as monocots (Collar 2016). One of the distinguishing factors of monocots vs. dicots is that dicots have a secondary growth phase (the fruit) whereas monocots only have one growth phase (Berkely 2015). This knowledge means that psuedocereals are more closely related to fruits than cereals. Psuedocereals play an important role in human nutrition in particular for those with allergies or intolerances to traditional cereals. (Fletcher 2016) Important nutritional components of psuedocereals include high protein which is important for many of the body’s functions. They also are high in dietary fibre which is invaluable for digestion. Some psuedocereals have been shown to contain polyphenolic compounds, such as phenolic acids

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and flavonoids. There is much interest in these because of their antioxidant and anticarcinogenic properties.(Ghasemzadeh and Ghasemzadeh 2011) Many psuedocereals are low impact plants which can be grown without the use of pesticides in harsh ecological conditions or marginal areas of cultivation (Coda et al. 2014) such as those found in third world countries. These have been inviting more attention in recent years due to suggested health benefits. These health benefits can also be contributed to the fact that these grains are often consumed as wholegrains (Coda et al. 2014). Breads produced with the use of these psuedocereals have been shown to have a softer crumb and more dietary fibre.

They have also been reported as having a higher antioxidant activity and polyphenol content when compared to other gluten free products on the market (Teagasc 2010).

1.7.1 Quinoa Quinoa (Chenopodium album) is native to South America and is often a constituent of breads in Peru and Chile. The nutritional properties of quinoa can be accredited to the high content of minerals, vitamins, fatty acids and antioxidants. The use of Quinoa flours is limited due to their low baking quality and the final quality of the baked products prepared with them (Coda et al. 2014). Quinoa is the only plant that encompasses all the essential amino acids, trace elements, and vitamins and contains no gluten. Quinoa has protein in the centre of the grain which differentiates it from cereals such as wheat where the protein is located in the hull (Collar 2016).The main protein found is wheat grains is gluten. Even though quinoa does not contain gluten it should be remembered that this does not mean it is lacking in protein.

Quinoa contains around 14-18% (Collar 2016) protein in comparison to 10-15% in wheat (Bridgwater and Aldrich 1968).

1.7.2 Quinoa Flour Quinoa flour is formed from the Quinoa seed which is found in the Andes. It has a higher protein content than other flours (McGee 2014). The protein content is around 8g per serving (Oelke et al. 2015). The high protein content can interfere with the baking process so it is often used in conjunction with other flours with a low protein content such as rice flour (Ogungbenle 2009). The use of quinoa flour may be beneficial in a diet of a person suffering with celiac disease as they normally have a lower intake of protein (Cappa et al. 2013).The use of quinoa flour alone can give dishes that have a gluey, heavy or sticky consistency which 20

not desirable. It can be made from milled or un-milled seeds. The un-milled seeds will yield a rougher and more nutritious flour (McGee 2004) which may add an interesting texture to the bread. However the milled flour has the advantage that it is smoother and will contribute smoother properties to the bread it is used in. The flour has a creamy yellow colour. This flour can be expensive to purchase and is most commonly kept chilled instead of at room temperature.

1.8 Fermented Foods Fermentation is a metabolic process through which carbohydrates and related compounds are oxidised and release energy.(Jay and Loessner 2015) During fermentation of foods chemical changes happen in an organic substrate as result of the actions of microbial enzymes.(Reed 2004) Fermented foods are most likely one of the first foods consumed by humans. This was not always by choice often fermentation occurred due to uncovered food being left in an otherwise unpreserved state.(Hutkins 2006) Fermented products remain a central part of the daily diet of the public not only for their attractiveness but for the improvement of the shelf life and the nutritional properties which are initiated by the fermentation process. In western countries food fermentations are often incorporated into the marketing policies of products as part of nutritional claims. This is often done in response to the increased attention of consumers to adopt a healthy way of life (Coda et al. 2014). Fermented foods are also popular due to their organoleptic characteristics (Coda et al., 2014) Fermented foods are currently gaining dominance in the food industry due to the clean label approach which still provides high quality cereal products (Poutanen and Katina 2014). Awareness of fermented foods is important now as the increasing introduction of industrially produced food stuffs is running the risk of displacing the traditional and healthy fermented foods (Coda et al. 2014).

1.8.1 Fermentation of Cereals The fermentation of cereals is affected by many different properties including the type of cereal, the native microbiota of the grains and the endogenous (Coda et al., 2014) and exogenous (De Vuyst and Neysens 2005) factors in the grains and technological parameters.

The endogenous factors are determined by the microbial and chemical composition of the dough (De Vuyst and Neysens 2005). The exogenous factors are affected mainly by temperature and the redox potential (De Vuyst and Neysens 2005). If the fermentation 21

process fails then spoilage and/or the survival of pathogens which can occur and be detrimental to the quality and safety of the product (Coda et al. 2014).

1.9 Bread Making and Methods.

Bread making is one of the oldest technologies known to mankind. The objective is to convert cereal flours into attractive, palatable, and digestible food (Chavan, 2015) Evidence suggests that bread has been consumed as part of the human diet for as long as 23,000 years (DovesFarm 2015). The foremost quality characteristics of leavened wheat breads is a soft and elastic crumb, high volume, and a good shelf life. From a safety point of view it is important that products be safe microbiologically (Chavan 2015). There are three main different methods currently in use for bread making – Straight dough method, Chorleywood method and the Sponge method.

1.9.1 Straight dough Method The straight dough method is the simplest form of dough production and has only one stage.

All ingredients are mixed in the bowl at one time. It does however a disadvantage. As the dough is all mixed at one time the yeast or starter culture may not be evenly distributed throughout the mix and so the bread may not be evenly fermented (Gisslen 2008). For this reason extra yeast may be used.

1.9.2 Sponge Method The sponge method is slower than the straight dough method (Scott et al. 1990). This is the most traditional of the bread making techniques and requires little yeast. However it was given up by many bakeries in the mid 50’s as the price of commercial yeast was dropping and the straight dough method was now more economical. In the sponge method most of the water and some of the yeast is allowed to preferment for 12 hours and this is then used as the leavening agent for dough preparation.

Preparation of the sponge is quick and the final

sponge has high fluidity allowing the yeast to be evenly distributed in the dough giving a rapid final fermentation. During this long pre-fermentation, flavours are produced that are not achievable using the straight dough method (McGee 2004). It is this method that is used in the production of sourdough bread.

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1.9.3 Chorleywood Method The Chorleywood method was invented in 1961. Using this method the first fermentation stage takes only a few minutes of intense mechanical dough working. A machine is used to rapidly stretch the dough. Yeast is required to produce carbon dioxide and aerate the bread.

(Robinson 2001) In this method twice as much yeast is used and flour improvers may also be utilized. Bread made using this method is often referred to as mechanically developed dough.

One of the advantages of the Chorleywood method is that almost any flour can be used to develop a high quality bread.(Lean 2006) 1.10 Process variables 1.10.1 Dough Yield Dough is a homogenous mixture of protein, starch, protein, fat, yeast, and salt. In the case of sourdough, LAB are also present in this homogenous mixture (Song and Zheng 2007).

Dough yield is the proportion of flour to water, it is frequently referred to as the DY and is defined as: Dough Yield= ((Amount of Flour+Amount of Water)*100)/ (Amount of Flour) (Chavan 2015) A low dough yield will result in a large loss of the raw materials (Stear 1990).

1.10.2 Temperature The temperature at which the LAB will develop can range from 30°C – 40°C (Stear 1990) The most crucial variable which must be considered in the production of sourdough is temperature, which must be maintained throughout the process from mixing up until the final proof. By doing this, the rate of the flour component modification and the changes in pH and gaseous contents will be synchronized (Stear 1990).

1.10.3 Starter Culture.

A starter culture is a microbial preparation of cells that is added to a raw material to produce a fermented food by accelerating and driving its fermentation process (Coda et al., 2014) The

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sourdough microflora is dominated by LAB and, along with yeast, they have a key role in the fermentation process (Chavan, 2015) Sourdough starters may be freshly prepared in bakeries or may be ordered from commercial suppliers in either living, liquid, dough, dried or non-fermenting sourdough forms (De Vuyst and Neysens 2005).

LAB increase the shelf life by producing antimicrobial substances including organic acids, CO2, ethanol and hydrogen peroxide. These are effective against foodborne pathogens and food spoilage bacteria. (Chavan 2015) Some starters have been shown to inhibit the growth of Aspergillus, Fusarium, and Penicillum. (Rollán et al. 2010) This knowledge means that sourdough breads can be effectively produced and preserved without the use of chemical preservatives giving a “clean label” product (Chavan 2015). It can also remove the need for Modified Atmosphere Packaging (MAP) (Arendt et al. 2011) which is expensive. MAP involves a blend of pure oxygen, carbon dioxide and nitrogen within an impermeable package (McGee 2004) to extend the shelf life. The amount of starter culture used is dependent on the type of process being followed but a guideline would be around 0.5% of total flour weight. This can go up to 20% depending on the desired characteristics of the finished product (Stear 1990). The maturing time can be adjusted by adjusting the amount of starter culture used (Stear 1990).

1.11 Sensory Analysis Sensory analysis is an analysis that measures human responses to the composition of a food product. The responses can be based on appearance, touch, taste odour, temperature and texture.(FOOD 2015) Sensory analysis can be used to find the similarities or differences in a range of products, to gauge if a product is acceptable to the consumer and also to provide feedback so as decisions can be made about further adjustments to a product.

In order to define the sensory qualities of a new product a sensory panel is often used. In an experimental setting it is an ideal opportunity for food technologists and scientists to get feedback on test products. Sensory testing areas are designed as atmospheres conductive to concentration. Conditions are controlled in order to reduce bias, improve accuracy and improve sensitivity.

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The practice of sensory evaluation has grown significantly in the second half of the 20 th century and it is a unique method to determine a customer’s perception of a new product before the launch. One of the most important things to consider when designing a sensory analysis questionnaire is that the right questions are asked. In the mid 80’s Coca cola launched a new product termed “New Coke”. The new product was sweeter and 200,000 blind taste studies were conducted. Testers did prefer the new coke over the other samples provided but they were not told that this product would be a replacement. Due to this error in the market research the company lost millions. (WPA 2009) It is also important to avoid bias in a sensory test. In order to ensure no bias in a sensory evaluation it is essential that panellists rinse their pallet before each sample. For smokers it is important that they have not smoked in the two hours prior to the test. The timing of the test is also important. Sensory tests are not commonly carried out on a Monday when the panellists may be feeling pessimistic, or on a Saturday when the panellists may be feeling optimistic. Sensory evaluation is best conducted on an empty stomach (Meilgaard et al. 2006).

Conclusion Sourdough bread is a combination of water and flour that has been fermented by LAB. Research indicates that this method of bread production has many beneficial effects, for health for quality and for the shelf life of the product. Many of these beneficial properties may be useful if applied to gluten free bread as research indicates, that they have been deemed undesirable when compared to their wheat based counterparts. Although much research has been done on the effects of sourdough on wheat based breads, this project aims to investigate the effects of sourdough production using gluten free flours in the production of bread suitable for coeliacs.

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2.0 Materials and methods: Three bread types were made, Gluten Free Type 1 sourdough (PHE) Gluten Free Type 2 (GTH) and Type 1 sourdough containing gluten. (RAC) Codes were provided in order to avoid the introduction of bias during sensory analysis.

2.1 Ingredients for Bread Gluten Free Type 1

Gluten Free Type 2

sourdough 210g Rice Flour 210g Quinoa Flour ¼ tsp cream of tartar 50g of Sugar 2 tsp xantham gum 1 ½ tsp salt 2 tsp baking soda 500ml gluten free sourdough

sourdough 210g Rice Flour 210g Quinoa Flour ¼ tsp cream of tartar 50g of Sugar 2 tsp xantham gum 1 ½ tsp salt 2 tsp dried yeast 235ml gluten free sourdough

starter 3 tbsp butter 360ml milk

starter 3 tbsp butter 360ml milk

Type 1 sourdough 420g wholemeal flour ¼ tsp cream of tartar 50g sugar 1 ½ tsp salt 2tsp dried yeast 235ml gluten free sourdough 3 tbsp butter 360ml milk

Method 1. A loaf tin was greased and set aside 2. The butter was melted in the microwave at a low setting and left to cool.

3. Using a standing mixer with a kneading attachment the flour, xanthan gum, cream of tartar, sugar, salt and yeasts were mixed and combined well.

4. The gluten free sourdough starter and the butter were added.

5. The milk was heated on the stove until a temperature of 37°c was reached taking care not to burn.

6. With the mixer on a low speed the milk was poured in slowly.

7. When the mixture had incorporated all the liquids, the speed was increased and it was mixed for 5 minutes.

8. The dough was moved to the greased loaf pan and the surface was smoothed over with a wet utensil.

9. The dough was left to proof for 45minutes, the oven was preheated to 160°c 10. The loaf was baked in a fan oven for 40 minutes.

The same method was followed for all bread samples but ingredients are substituted as stated in the ingredients.

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2.2 Sensory Evaluation

Two questionnaires were utilized in this project. One questionnaire was aimed at people who do not have coeliac disease in order to determine the acceptability of the samples to the general public. This questionnaire included some qualitative questions in which the participants were asked to describe the bread samples using a single word. 48 students completed this questionnaire.

The second questionnaire was aimed at coeliacs only and there was three bread samples for them to evaluate. By combining the information retrieved from the two sample groups the bread samples were analysed for their organoleptic qualities. 10 coeliacs completed this questionnaire.

Samples of questionnaires can be found in the appendices below.

2.3 Physical attributes testing: Characteristics of Bread The physical attributes of the breads were tested in order to determine the quality. These tests were volume and density, moisture content, shelf life, colour analysis and texture.

2.3.1 Volume and density Bread volume and density was measured using a ruler. Samples were measured for length breadth and height. The mass was also recorded using a calibrated laboratory scale. Density was found by dividing the mass of the sample by the volume.

2.3.2 Colour: Colour of both the crumb and the crust were analysed using a handheld LAB meter. L in the LAB test represents the lightness of the surface from 0-100, A and B are measurements of the red to green and blue to yellow respectively.

2.3.3 Moisture Content Moisture content of the prepared and commercial samples was determined by pre-weighing a sample and crucible separately and then placing the sample in the crucible in the oven at 80°c and weighing them after 24 hours. Moisture content was determined by the % mass loss in the samples during this period.

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2.3.4 Texture Texture of the prepared samples and the commercial samples was determined using the LFRA texture analyser which is the industry standard for texture anlysis, with different probe attachments depending on the bread sample being analysed. The crust was measured using the needle probe which indicates the crispiness of the bread and the crumb texture was analysed using the compression probe which give a measure of the springiness and therefore freshness of the bread samples. All measurements where completed to a depth of 5mm.

2.4 Microbiological Testing A Growth curve was prepared for the Sourdough starter. Samples were taken hourly over 2 days and plated on MRS agar.

2.4.1 Production of a Growth curve for Sourdough Starter Culture 1. 10g of the starter dough was aseptically transferred into a stomacher bag with 90mls of ringers and left to homogenize for 10minutes.

2. This was placed in a beaker and labelled 10-1.

3. Serial dilutions were made and were plated to determine which dilution would be used for the growth curve 4. Plates were incubated anaerobically for 48 hours 5. A dilution of 10-5 was observed as the optimum dilution to analyse the death rate of the sourdough microbes.

6. A dilution of 10-5 was prepared hourly and plated on MRS agar.

7. Samples were plated in duplicate over two college days and then placed in the incubator for 48 hours.

8. Results were analysed.

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3.0 Results

Table 3. 1 Bread type analysed Sourdough Type Type 1

Description This type is prepared using a starter which does not have added

Type 2 Type 3

yeast This type is prepared using a starter with added yeast This type is prepared using a dried starter culture (Commercial products)

3.1 Sensory Analysis results

3.1.1 Results of preference sensory testing by LYIT students.

This analysis asked the students to taste five bread samples two which were commercial and three which were baked in the food technology labratory. Samples were randomly coded and students were unaware which samples were commercial, gluten free or standard. Students were instructed to taste the samples and then move position to the next sample in a clockwise manner. Students rated the samples on a scale of 1-10 with one being extremely dislike and ten being extremely like. The results are shown here in Table 3.2

Table 3. 2 Preference Scores for Sourdough samples determined by 48 LYIT students and staff Rating

1

Type 1

Type 2

Kelkin gluten

Sample

Aldi

Sourdough

sourdough

free Sourdough

with Gluten

Sourdough

3

(Type 3) 2

(Type 1) 0

(Type 3) 0

3

29

2 3 4 5 6 7 8 9 10

3 9 7 11 5 5 2 3 1

6 5 5 9 11 5 1 2 1

11 4 3 6 9 7 4 2 1

0 0 3 2 6 13 13 8 4

1 2 1 3 7 6 12 9 9

Table 3. 3 Mean, Standard Deviation and Mode for Sourdough samples Type of Sourdough Type 1 gluten free

Mean 4.84

Standard Deviation ±2.20

Mode 5

Type 2 gluten free

4.76

±2.17

6

Kelkin Gluten free

4.92

±2.41

2

Sourdough

7.45

±1.53

7

Aldi Sourdough

7.40

±1.97

8

Graph representations of these results for the 48 participants are shown below in Figure 3.1, 3.2, 3.3, 3.4, and 3.5

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Figure 3. 1 Preference Results for Type 1 Sourdough determined by LYIT students and staff

Figure 3. 2 Preference Results for Type 2 Sourdough determined by LYIT students and staff

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Figure 3. 3 Preference Results for Kelkin Sourdough determined by LYIT students and staff

Figure 3. 4 Preference Results for Type 1 sourdough with gluten determined by LYIT students and staff 32

Figure 3. 5 Preference results for Aldi Sourdough (With gluten) determined by LYIT students and staff

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3.1.2 Descriptive analysis

All students and staff also qualitatively analysed the provided bread samples by describing the samples in one word. The most commonly used words for each sample are tabulated below in Table 3.4 Table 3. 4 Results of descriptive analysis determined by LYIT students and staff Descrptiv

Type 1

Type 2

Kelkin gluten

Sample

Aldi

e word

Sourdough

Sourdough

free Sourdough

with

Sourdough

0 0 0 8 3 0 0 2 0 1 3 3 1

Gluten 0 1 1 0 2 2 0 3 0 0 0 1 3

0 2 2 0 3 1 0 2 0 2 1 1 2

used Bad Bland Chewy Dry Light Lovely Moist Nice Nutty Soft Sour Stale Tasty

0 1 2 1 1 0 2 2 3 2 1 0 0

3 1 5 1 1 0 1 0 4 0 1 0 1

3.2 Physical Attribute Testing: Characteristics of Bread

The following physical characteristics of the bread samples were analysed- Volume and Density, Texture of crust and crumb, Colour of crust and crumb, and moisture content 3.2.1 - Volume and Density

Table 3. 5 Volume and Density of Bread samples Measurement

Type 1

Type 2

Type 1

Aldi

Kelkin gluten free

s

Sourdoug

sourdoug

with gluten

Bread

sourdough

h

h 34

Height (cm) Length (cm) Width (cm) Volume (cm3) Mass (g) Density(g/cm3

8.5 5 2.1 89.25 84.6 0.95

4.40 6.00 1.30 34.32 24.26 0.71

6.2 5.8 2.1 75.52 21.35 0.28

9.20 5.40 1.80 89.42 39.13 0.44

8.40 7.30 1.60 98.11 19.85 0.20

)

Figure 3. 6 Density of Bread Samples 3.2.2 Texture Analysis of Bread samples

For the texture analysis of the bread samples three texture measurements were taken for both the crust and the crumb of the samples and an average taken all results are shown below.

Table 3. 6 Texture analysis of crust of bread samples using needle probe at a depth of 5mm Type 1

Type 2

Type 1

Kelkin

Sourdoug

Sourdough

Sourdough with

Sourdough

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Aldi Sourdough

h Texture 1 (g) Texture 2 (g) Texture 3 (g) Average (g)

gluten

485 86 137 236

135 256 95 162

95 114 151 120

664 279 501 481

145 243 375 254

Table 3. 7 Texture analysis of crumb of bread samples using a plastic ball probe to a distance of 5mm Type 1

Type 2

Sourdoug Sourdough

Type 1 Sourdough

Kelkin

Aldi

with gluten

Sourdough

Sourdoug

Texture 1

h 26

58

110

34

h 100

(g) Texture 2

51

65

74

41

88

(g) Texture 3

57

79

132

28

123

(g) Average (g)

45

67

105

34

104

36

Figure 3. 7 Texture analysis of bread samples

3.2.3 Colour analysis of Bread samples

For the colour analysis of the bread samples three measurements were taken of at different areas of the crust and crumb of the bread sample and averages were calculated.

Table 3. 8 Colour analysis of crust of Bread Samples Type 1

L* A* B*

Type 2

Type 1

Kelkin gluten

Sourdoug sourdoug

with

free sourdough

h 40.54 9.05 17.18

gluten 38.73 1.29 22.67

44.08 10.08 19.5

h 25.04 5.42 6.3

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Aldi Sourdough

39.55 8.76 15.51

Table 3. 9 Colour analysis of crumb of bread samples

L* A* B*

Type 1

Type 2

Type 1 with

Kelkin

Sourdough

sourdough

gluten

gluten free

63.35 4.23 17.63

sourdough 64.91 -0.21 18

45.14 4.97 14.31

51.46 4.67 14.71

Aldi Sourdough

Figure 3. 8 Comparison of L* Values for crust and Crumb of Bread Samples

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68.04 -0.68 9.92

3.2.4 Moisture Content Determination

For the moisture content of the bread samples three samples were weighed and placed in the oven at 80°c for 24 hours. The dried samples were weighed and the average and the moisture content calculated.

Table 3. 10 Moisture Content of Bread Sample

Moisture

Type 1

Type 2

Type 1

Kelkin

Aldi

Sourdough

Sourdough

Sourdough

Sourdough

Sourdough

38.15%

with gluten 48.89%

30.55%

35.54%

57.77%

Content

Figure 3. 9 Moisture Content of bread samples

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3.3 Microbiological Testing of Samples

Table 3. 12 Cfu count completed over a period of 23 hours Time (hours)

CFU

0

9.5 x 106

1

1.6 x 107

2

2.1 x 107

3

2.2 x 107

4

2.2 x 107

5

2.1 x 107

20

1.1 x 107

21

5.4 x 107

22

2.1 x 106

23

9.0 x 105

Figure 3. 10 Growth/Death Curve for LAB in Sourdough Culture

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4.0 Discussion Sourdough starters were prepared for this project. Starters were made using gluten free rice flour and quinoa flour. The type 2 sourdough starter was inoculated with 2g of yeast on week two of feeding. Due to time constraints the starters were fed twice daily in order to be ready in time for the analysis. If this experiment were to be conducted again the cultures would be started earlier in order to have more conclusive results. The increased frequency of feeding did not appear to have a detrimental effect on the loaves prepared but may be the reason that a change in the recipe was required. When the starter showed signs of life (Bubbling and fizzing) the frequency of feeding was reduced to once every 48 hours. This occurred around week five. The breads were prepared using the starter on week’s 9-12 after initiation.

Prior to conducting tests on loaves prepared a number of “test runs” were completed to determine the best possible recipe and rising times for the final samples analysed. The first loaves prepared using standard sourdough ingredients did not rise sufficiently when baked.

As yeast requires heat to multiply it was determined that in order to achieve a rise in the type 1 gluten free that the starter must be incubated at 37°c for two hours prior to baking. As a result two different incubation temperatures were used for each of the two starters. Type 1 gluten free was incubated at room temperature and type 2 gluten free was incubated at 30°c.

As the bread was still not rising adequately, it was also determined that milk was required in order to provide extra nutrients for both the young sourdough starters. This may not have been the case in an aged starter but it was necessary in order to achieve the required rise in volume with a young starter. With these changes in place the bread was now rising sufficiently but large gaps were observed the dough had broken were observed after baking.

Large gaps or holes are characteristic of sourdough however these were too large. In order to prevent this, fat was also added to the recipe in order to make the bread more resistant to stretching during baking and an additional benefit of this is that the crumb was made softer by the increased fat content.

The purpose of this practical was to determine if the use of sourdough technology could improve the qualities of gluten free bread. The quality of food as with any product is determined in the eyes of the customer. For this reason sensory analysis forms an integral part of this experimental analysis. The sensory results can be used with the other data to determine which characteristics of the bread the consumer deems important and how sourdough could be used to achieve these in a gluten free bread.

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During the sensory analysis 48 students and staff were asked to taste and rate five bread samples on a scale with 1 being really dislike, and 10 being really like. Some limitations did exist in this part of the analysis. LYIT is not equipped with an industry standard tasting booth and so the products could not be masked in any way. As much as possible the identity of the products was disguised with the use of a randomized three digit code for each sample. Breads which contained gluten were disguised and only people with coeliac disease were informed which samples contained gluten The results of the sensory analysis show a very clear preference for samples which contain gluten. The sourdough prepared in the food laboratory achieved the highest ratings (MEAN 7.45; SD ±1.53) seen in Table 3.3. This sample has a mode of eight with 13 participants giving this rating. The type 3 Aldi sourdough which also contained gluten and was in 2 nd position (MEAN 7.40; SD ±1.97) this sample also had a mode of eight with 12 participants scoring this.

Analysis of the sensory results for the gluten free products shows a preference for the type 2 gluten free (MEAN 4.76; ±SD 2.17). These results do have a large deviation from the mean showing that there was a substantial disagreement between participants on the palatability of the bread samples. The results for the prepared type 1 gluten free and type 2 gluten free are very similar. From this we could assume that if marketed the consumer would not be able to differentiate between the more natural and healthy type 1 and the more processed type 2 varieties.

The least liked of the samples was the commercially produced Kelkin gluten free sourdough.

(MEAN 4.92; SD ±2.41) with 11 people rating the sample only 2.

There is a possibility that masking of the bread samples may have had an effect on these results as the most preferred samples were white which is the most commonly chosen in supermarkets. All these results are further highlighted in the series of graphs (Figure 3.1 Figure 3.5) In addition to rating the samples the participants were asked to describe the each sample using a single word. Results of this descriptive analysis are shown in Table 3.4. These words can now be used with the ratings to determine what people perceive as important characteristics of bread.

42

The only bread sample which was described as “bad” was the type 2 gluten free which came fourth in the sensory analysis. Five people described the bread sample as chewy. As only one person described the sourdough as chewy it can be assumed that chewy is an undesirable characteristic of bread. However it must be mentioned that this is a common characteristic of sourdough bread. Additionally four people described this sample as having a nutty taste. This nutty aroma and flavour was attributed to the bread by the high protein quinoa flour. As this word was not used for any of the other samples it is not possible to determine if nutty is a desirable or undesirable characteristic.

The Kelkin sourdough which was the least favoured of the bread samples was described by eight people as “dry”. This is the most stated word in the entire survey so it can be concluded that dry is the least desirable characteristic. There is some confliction of results as no participants described the favoured samples as moist which may be an indication that it is a middle ground which is desired. The Kelkin sample was also described by three participants as stale. As the product was provided vacuum packed and opened 30 minutes prior to analysis it was not stale and the reason for this perception may be the dryness which was also indicated. Three people did describe the Kelkin sample as light with only two stating this for the favoured sample. This indicates that the presence of one given attribute is not enough to make the product desirable and must be present as part of a “perfect balance”. Words like nice, lovely, and tasty were most commonly used to describe the preferred sourdough which shows that perhaps the panellists themselves were unaware of what makes them like the bread they like. These results may not be considered at statistically significant as a number of participants did not complete this aspect of the survey.

In order to determine more conclusively what the customer requires from bread a series of quantitative tests were also completed. A simple volume and density measurement of the samples was carried out and the results of these are shown in Table 3.5. These show that the least dense bread which had the highest volume was the least desirable. The Kelkin sample has an average density of 0.20g/cm3 compared with 0.28g/cm3 for the Sourdough. This is only 0.08g/cm3 of a difference as such it is not conclusive that it was the lack of density which made the product undesirable. However the Kelkin was previously stated as being “dry” so this low density may be as a result of the low moisture content. The Aldi sample had a density of 0.44g/cm3 which is substantially higher than the other sample containing gluten.

This bread was commercially prepared using type 3 sourdough technology (a dried starter culture) which when hydrated may have contributed to the increased density of the final loaf.

43

Analysis of the density of the prepared gluten free sourdoughs shows a considerable difference. It appears that the type 1 gluten free is the heaviest of all the samples with a density of 0.95g/cm3. When compared to sourdough there is clear evidence that the presence of gluten attributes a lightness or airiness to the bread. By looking at the density of the Kelkin it appears that using type 3 sourdough technology may be the way to achieve this in the absence of gluten. A graph is shown in Figure 3.6 which illustrates that the absence of commercial yeast gives a denser product unless gluten is present. Although these results are accurate for this experimental analysis, they will not be true in the case of all sourdough breads. A more established starter would contain more wild yeast and so it is likely to vary greatly in density with the extra CO2 being produced.

Further attribute analysis was done on the texture of the breads using a texture analyser. The results for the crust are shown in Table 3.6. The load in grams to pierce the section of the crust was determined using a needle probe. The highest load was required for the type 3 Kelkin bread with 481g. This is a predictable results as it was described as dry. With a low moisture content there would be little moisture at the surface of the bread. This hard crust was a quality of the least likeable bread sample tasted, and is due to the presence of buckwheat flour in Kelkins recipe which is not commonly ground as fine as other flours. The next hardest crust analysed was the Aldi type 3 sourdough it is possible that this hard crust is a characteristic of this type of sourdough. This hardness is more pronounced in the gluten free sample as the Aldi sample had a load of 254g. The type 1 gluten free and the type 2 gluten free have a large difference in the load which was required to pierce the crust. This is a result of the fermented sugars produced by the baker’s yeast in the type 2 gluten free sample. The fermentable sugars are less rigid and more easily broken down than the starch which is present in larger quantities in type 1. The softest crust was the crust of the sourdough. This soft crust can be attributed to the action of the yeast in contact with a flour which has a higher sugar content. A graph is shown in Figure 3.8 which shows type 3 sourdough to give a harder crust but this is lessened in the presence of gluten. As the hardness of both the crust and crumb of the bread samples can vary depending on the methods and the ingredients used there is no literature value and these results are comparable only to each other.

Table 3.7 shows the results from the texture analyser for the crumb of the bread. This was done using the plastic ball probe on the texture analyser which measures the load in grams required to compress the crumb. This probe also functions to measure the hardness or softness of the bread in the mouth without being worked on by the teeth. In a complete 44

reversal of the crust analysis the crumb of the sourdough has the hardest crumb with a required load of 105g. This hardness is due to the strong gluten protein network which is formed in the bread during mixing. Where there was a significant difference required for the crust of the two gluten samples there is only a 1g difference in requirement in relation to the crumb. This is an indication that the springiness of the crumb is determined by the protein present and the Aldi recipe also used fat. Of the gluten free samples the hardest crumb is present in the type 2 gluten free sample. The reason for this is unknown and may be insignificant as there is little variation in this and the type 1.The comparatively low load requirement for the gluten free samples indicates the absence of gluten leads to a hard crust but a soft crumb. It is interesting to note the relationship which exists between the crust and crumb which is highlighted in Figure 3.8. If a bread has a soft crumb, it will have a hard crust and vice versa. From conducting a comparison between these results and the sensory analysis it appears that the most desirable combination with texture is a soft crust and a less springy crumb.

As previously mentioned the appearance of the bread samples was not masked during the sensory analysis and for this reason the bread samples were analysed for their visual appeal using a LAB colormeter. The results of this analysis on the crumb of the bread samples is shown in Table 3.8. The lightness and darkness of the samples is measured using the L* value the closer this value is to 0 the darker the sample is and the closer to 100 indicates lightness.

The type 1 sourdough and the Aldi sourdough are very similar in the darkness of the crust with 38.73 and 39.55 respectively but they do differ greatly in the amount of red with 1.29 and 8.76 respectively. The increased red in the crumb appears to the eye as an appealing golden bake. This can be achieved using a high heat which is common in commercial baking (Mohd Jusoh and Chin 2009). The type 2 gluten free has the darkest of all the crusts which is further explained by the lowest amount of yellow present 5.42. This dark colour can be attributed to the use of quinoa flour and rice flour two products that are dark from harvest to production. Both of these are high in carbohydrates and with the added sugar this would cause the malliard reaction or ‘browning’ which can be seen on the crust of the bread.

The type 1 gluten free has one of the lightest crusts and also has the 2nd highest degree of red. The Kelkin was shown to have the lightest crust of the five samples and also the highest amount of red though there was little variation between this and the type 1 gluten free. The slightly more red quality to the crust could be contributed to the extra carbohydrate which is present which is “singeing” the bread giving this reddish tinge and also the buckwheat flour 45

which has some red present. As previously mentioned a high temperature can also contribute a red quality to the crust and so fluctuations in temperature in the oven could be responsible for the difference in the amount of red present in prepared loaves.

In analysing the amount of yellow present in the crust the Aldi sample displayed the 2nd highest total of yellow present with a B* value of 15.51 but this is a large difference from the other gluten sample which displayed a B* value of 22.67. This indicates that the degree of yellow is not determined by the gluten content but is determined by the type of sourdough production used. The Kelkin sample displayed a large amount of yellow double that of its red content which explains the light appearance of the crust. The gluten sourdough has the largest amount of yellow present which is predictable given it was prepared with a wheat flour.

Both the crust and the crumb were analysed using the LAB colormeter, the results for the crumb are shown in Table 3.9. The type 1 gluten free has the darkest crumb of the samples with an L* value of 45.14 with type 2 gluten free slightly higher at 51.46. This is a predictable result as the Quinoa flour used for these is a dark colour. There is a large difference between this and the crumb of the gluten sample which had a value of 63.35 due to the wheat flour. The Kelkin and the gluten Aldi sample were the lightest of all which may be due to the bleaching agents present which are commonly used in mass production of bread products. The Aldi and the Kelkin again display similarities in the degree of red present with neither entering the red scale of the LAB model. As the type 1 and type 2 samples are all present on the red scale in similar quantities it may be a result of the type 3 production process that eliminates the red pigment from the crumb. These breads do differ greatly in the amount of yellow present in the crumb with the Aldi bread displaying the least and the Kelkin displaying the most. As previously mentioned a bleaching agent has been used in the Aldi and Kelkin samples which gave them the lightly coloured crust and crumb. Type 1 gluten free and type 2 gluten free are very similar in the amount of yellow present with 14.31 and 14.71 respectively. This is not surprising as there was little variation in the method or the ingredients used which could have impacted the colour. The sourdough was the second most yellow sample used due again to the wheat flour. The crumb was also light with moderate red content and a large proportion of yellow. When comparing these results to the results of the sensory analysis it appears that the most testers visually preferred a light crust with a moderate amount of red and a significant amount of yellow, attributes common to white bread.

46

The relationship between the darkness of the crust and crumb of the bread samples is shown in Figure 3.8 above. As shown a constant relationship exists except in the case of the type 1 gluten free were the crust and crumb are very closely related. This may be as a result of the decreased presence of yeast to ferment the sugars present to darken the crust.

Table 3.10 highlights the results recorded for the moisture content of the bread samples. It can be seen here that the highest moisture content was recorded with the type 1 gluten free with a moisture content of 57.77%. Even with this high moisture content it was described as dry by 1 participant of the sensory analysis but correctly described by two of the participants as moist. A standard bread dough will have a moisture content of around 40% (Classofoods 2016). The formulation for this sourdough bread asked for 500ml of sourdough starter culture which was in a liquid form so a final product with a high moisture content is expected. A larger volume of sourdough starter was required for the type 1 gluten free than the type 2 gluten free as it is a young culture and did not display sufficient rising ability when used in smaller quantities. These sourdough samples were the only two which were described as moist in the descriptive analysis. The sourdough with gluten has a high moisture content also at 48.89%. This again can be attributed to the liquid sourdough starter used. The lowest moisture content was found in the two type 3 sourdough starters. This is a common occurrence with shop bought sourdoughs as when made in bulk the starter culture is not normally added in its liquid form and the surface may not be moistened prior to baking. The results of this test show that the sensory panel did correctly identify the Kelkin sample as the lowest moisture content with eight participants describing it as “dry� and the least favoured sample. This confirms earlier assumptions that the hard crust and the low density were a result of lower moisture content. The Aldi sourdough which came second in the sensory panel was not described as dry by any participants although its moisture content was only 3% higher. This indicates that even a slight increase of the moisture content can lead to a bread which is more palatable. The sourdough which was favoured in the sensory analysis had a moisture content of 48.89%. The large difference between the moisture content of the two favoured samples is an indication that the moisture content of a bread sample is not an important factor in the palatability of the bread so long as the moisture content exceeds 35%, and as the type 2 gluten free was considered mediocre in the sensory analysis it can be assumed that an exceedingly high moisture content is less undesirable than a low moisture content.

47

Table 3.12 illustrates the colony count of the LAB on the two sourdough starters over two days. As only LAB measurements were taken and not yeast the results had very little variance and so a single result is shown. For the growth curve of the culture a sample was lifted hourly during college hours and then as seen in figure 3.12 there was gap of 15 hours in which no samples could be taken. This does mean that the results may not be as accurate as possible but it is illustrated that after feeding there was a rapid period of growth which continued until the fourth hour during which the growth entered the stationary phase of its growth. When counting was resumed at the 20th hour the starter was in the death phase. Although there was an increase from 1.1 x 107 to 5.5 x 107 between the 20th and 21st hour. This suggests that when the culture was disturbed there was a distribution of the flours and some rapid growth. The growth resumed its decline in the 22 nd and the 23rd hour recording 9.0 x 105 at its lowest. This is 10.6 times lower than the measurement in the minutes after feeding and does suggest that the culture should be fed every 24 hours in order to maintain growth. The sudden peak in growth at 21 hours due to the disturbance of the culture may be an indicator that mixing the culture every 12 hours may have been sufficient at the beginning rather than providing more feed. There is room here for extra study into the growth curve of this young culture and the growth of a more mature culture. There is also research that could be done on the different strains of LAB and yeast which were discussed in the literature review and their relationship with different flours and various aged cultures. These results also illustrate the ease of which sourdough bread which is a healthy alternative to standard bread can be prepared at home.

5.0 Conclusion During this practical the effects of sourdough technology on the quality of gluten free bread was investigated. As quality is a measurement of the expectations of the customer in relation to the perceptions of the customers to the final product. For this reason sensory analysis forms a major component of this project.

This sensory analysis did show a preference for the samples which contained gluten with both the prepared and the commercial gluten product claiming the top two positions.

The commercial gluten free sample “Kelkin” was the least preferred being described as “dry” and “stale”. Analysis of the characteristics of this bread showed this bread to have a low density similar to the favoured gluten sample. This is an indication that density was not an important factor in the panel’s choice of sourdough. A Soft crust was preferred by the panel 48

with a hard crumb. The soft crumb is achievable using a high sugar flour or adding more sugar to the formulation of gluten free sourdough. The hard crumb is a characteristic of gluten breads and further analysis should be done to achieve this without the use of gluten. As other proteins such as those in the Quinoa flour did not provide this.

A light golden crust was preferable to a dark crust. A light crumb was also preferred to which was achieved in the gluten samples using a bleaching agent. As gluten free flours are normally wither a darker colour or low in protein then bleaching agents may be used, which was the case in the Kelkin. It appears that a lighter crust will result in a lighter crumb so it is a balance of the ingredients which is required.

Moisture content did not have a significant effect on the panels choice of bread provided this moisture content was above 35%.

The ease of the production of sourdough is demonstrated here through the microbiological testing although it is important to prepare the starter culture in the months prior to baking the bread in order to have a higher quality product.

Further analysis should be done using different flours and different maturities of starter culture. Also the qualities of commercial gluten free bread and gluten free sourdough could be compared.

49

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55

7.0 Appendices Appendices 1 - Standard Questionnaire I invite you taste the presented samples from left to right. After each sample I ask you to rate the samples on a scale of 1-10 and then describe then using a single word.

Are you?

MALE [ ]

FEMALE [ ]

RAC 1[ ]

2[ ]

3[ ]

4[ ]

5[ ]

6[ ]

7[ ]

8[ ]

Extremely dislike

9[ ]

10 [ ]

Extremely Like

Please describe this sample in one wordPHE 1[ ]

2[ ]

3[ ]

4[ ]

5[ ]

6[ ]

7[ ]

8[ ]

Extremely dislike

9[ ]

10 [ ]

Extremely Like

Please describe this sample in one wordCHD 1[ ]

2[ ]

3[ ]

4[ ]

5[ ]

6[ ]

7[ ]

8[ ]

Extremely dislike

9[ ]

10 [ ]

Extremely Like

Please describe this sample in one wordGTH 1[ ]

2[ ]

3[ ]

4[ ]

5[ ]

6[ ]

Extremely dislike

7[ ]

8[ ]

9[ ]

10 [ ]

Extremely Like

Please describe this sample in one word-

PTO: 56

CHD 1[ ]

2[ ]

3[ ]

4[ ]

5[ ]

6[ ]

Extremely dislike

7[ ]

8[ ]

9[ ]

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Extremely Like

Please describe this sample in one word-

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Appendices 2 - Coeliac Questionnaire Are you: MALE [ ]

FEMALE [ ]

How long ago were you diagnosed with coeliac disease? <1 year [ ]

1-2 Years [ ]

3 years + [ ]

Do you purchase gluten free breads?

YES [ ]

NO [ ]

If yes â&#x20AC;&#x201C; What if anything would you like to see improved with gluten free breads?

Please taste the provided samples from left to right and rate them on the scale provided.

RAC 1[ ]

2[ ]

3[ ]

4[ ]

5[ ]

6[ ]

7[ ]

8[ ]

Extremely dislike

9[ ]

10 [ ]

Extremely Like

Please describe this sample in one word-

PHE 1[ ]

2[ ]

3[ ]

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Extremely dislike

7[ ]

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Extremely Like

Please describe this sample in one wordPTO:

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MKE 1[ ]

2[ ]

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Extremely dislike

7[ ]

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9[ ]

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Extremely Like

Please describe this sample in one word-

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Appendices 3 â&#x20AC;&#x201C; Physical Risk Assessment

Physical Risk Assessment

Task Bread Making

Description

Assessment By:

Use of the electric oven to bake bread.

Kerri Pope

Date of Assessment: 23/11/2015

Hazard

Current Risk

Harm or

Existing Controls

Loss

S

L

R R

Take care when opening or Oven

Risk of Burn

closing oven - surfaces are hot.

Take care when handling,

1

1

1

3

1

3

removing and baked goods in and out of oven.

Sharp Knifes

Risk of Cuts

Take care when preparing samples using sharp utensils

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Current Risk

Harm or

Hazard

Existing Controls

Loss

S

L

R R

Unplug equipment before Electrical

Electric Shock

cleaning or disassembling.

Certify hands are dry when handling all electrical equipment.

Appendices 4: Project Plan B.Sc. (Hons) Food Science and Nutrition Project 61

2

1

1

Project Plan Proposal Name: Kerri Pope Project supervisor: Mary Carr Project Title: Use of type 1 sourdough technology to improve the quality of Gluten free bread.

Aims of the project:  

To use sourdough technology in the production of gluten free bread To determine if the use of sourdough technology improves the quality of gluten free products.

Introduction For thousands of years bread has been a major component of the human diet. It has been hypothesised that people in Egypt, Rome and Greece ate bread long before the A.D. period.

(Rupesh S. Chavan Chavan, Shraddha R. 2015) Sourdough production can also be traced back to ancient times. The use of sourdough technology has remained popular due to its ability to extend shelf life and its superior sensory quality.(De Vuyst and Neysens 2005) Sourdough bread is predominantly flour and water and after several refreshments (5-7 days) a panel of LAB and yeast are found in what is now sourdough. These microorganisms are known as the microbiota.(Minervini et al. 2015). These microorganisms metabolize within the mixture and release Lactic acid and acetic acid into the mixture which gives the sour taste of the final product. They also release CO2 into the mixture which enhances the final breads volume. (De Vuyst and Neysens 2005) Coeliac Disease is an immune-mediated disease which is triggered in predisposed individuals when they ingest gluten. If a person suffering from CD ingests foods with gluten the body will form defensive antibodies against a portion of the harmless gliadin proteins in rye wheat, barley, a cross between wheat and rye called triticale and possibly oats. (Mayo Clinic Staff, 2015) i.e. all Triticum species (Masure et al.) CD affects 1% of the world’s population.

(Campo et al.). There are many theories as to why a person gets CD Most research indicates that it is a genetic inherited illness which determines that the linings of a person’s small intestine will be sensitive to gluten. As of yet there is no way of determining the genes to determine if a person has CD instead blood is tested for specific antibodies which will

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reliably indicate if a person has CD. There is as of yet no method for curing CD instead the treatment is total elimination of foods containing gluten from the diet. (Campo et al.)

Gluten free bread (GF) is different to bread made from gluten containing wheat grains particularly in relation to its sensory qualities. Studies have shown that both the texture and the aroma have been deemed undesirable.(Pacyński et al. 2015) There is a large interest in recent years in the development of palatable gluten free bread. Since 2010 more than 10 research articles have been published every year.(Masure et al.) Studies have indicated that by using sourdough technology the textural qualities, shelf life and overall quality of gluten free bread can be improved.(Campo et al.)

Ingredients & Materials                  

Quinoa Flour Rice Flour Whisk Small bowls Baking Tins Established Starter Culture Salt Sugar Xanthan gum Yeast Water Butter/margarine Crucibles LAB colorimeter Texture Analyser Ruler Oven Jar

Experiments/Methods: 1. Sourdough starter culture preparation.

2. Bread Sample Preparation 3. Characteristics of all bread samples.

• •

Volume and density.

Colour analysis.

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• •

Moisture content.

Texture.

4. Descriptive and Preference testing.

Experiment 1: Sourdough starter Culture preparation 1.

2.

3.

4.

130g of quinoa flour is whisked with 3 tablespoons of deionised water in a small bowl Pour into a jar and leave for 12 hours.

After 12 hours whisk in 65g of quinoa flour with 235ml of deionised water.

Continue adding 120ml of water and 45g of flour every 12 hours for one week. Until

the sourdough starter is bubbling.

5. A second starter is prepared using an established sourdough starter.

Note: As the starter is “Fed” care is taken to whisk in the flour and water thoroughly and to allow air into the starter

Experiment 2: Production of the three bread samples.

Recipe 1 - Standard Gluten Free Bread        

175g Quinoa Flour 175g Rice Flour 1tsp Salt 1tsp Sugar 1tsp Xanthan gum ¾ tsp Yeast 180-360ml Luke warm water 12g Butter/margarine

Method 1. Yeast is dissolved in lukewarm water and all ingredients are mixed together 2. The mixture is kneaded for 5 minutes and then left it to rest for 5minutes before kneading for another 10 minutes 3. The loaf is left to rise for approximately 30 minutes while covered with cling film 4. Cooked for 45 minutes at 220°c.

1. Gluten free bread made with homemade sourdough LAB culture 2. Gluten free bread with commercial sourdough culture.

Experiment 3: Characteristics of all Bread samples.

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Method for moisture content: 1. Crucibles are weighed and labelled.

2. Samples are placed in crucible and re weighed.

3. These are placed in an oven at 100°C for 24 hours.

4. Samples are weighed periodically until a constant weight.

5. Moisture content are determined by the loss in weight of the samples.

Method for texture analysis using the texture analyser: 1. Machine is turned on selecting appropriate probe.

2. One slice of bread is placed on the stage.

3. Stage is moved until the sample touches the probe.

4. The load is reset to zero.

5. Distance is set to 5 millimetres per second.

6. Ensure mode is set to zero.

7. Start button is pressed and record load will be recorded.

8. Reset button is pressed after each sample.

Note: The crumb is measured with a compression probe, while the crust is measured using a needle probe.

Method for colour analysis 1. The reflective colour of the breads is measured on crumb using a Colour Measuring System.

2. L, A and B values are recorded in five different places and an average is taken 3. This is repeated for the crust of all bread samples Method for volume and density

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1. Volume and density is measured by using a ruler and measuring the bread samples volumes and density.

Experiment 4. Descriptive and Preference testing.

Descriptive Testing Food Science students will be asked to taste three samples of bread and rate them on a scale based on the intensity of different characteristics of the bread.

Preference Testing Students will be asked to taste three samples of bread and rate them in order of preference.

This test will also ask if the person would buy their favoured product if they knew it had more health benefits in comparison to standard gluten containing bread.

Experiment 5: Microbiological Testing Test to enumerate lactic acid bacteria in the starter culture 9. 10g of the starter dough is aseptically transferred into a stomacher bag with 90mls of ringers and left to homogenize for 10minutes.

10. This is placed in a beaker and labelled 10-1.

11. Duplicate plates of 10-1, 10-2 and 10-3 pour plates using MRS medium which has been adjusted to a pH of 5.5.

12. Plates are incubated for 2days at 30°c.

13. Remove plates from incubator and count.

Test for presence of Heterofermentative LAB 1. 10g of the starter dough is aseptically transferred into a stomacher bag with 90mls of 2.

3.

4.

5.

ringers and left to homogenize for 10minutes.

This is placed in a beaker and labelled 10-1.

0.1ml of this is transferred to a tube containing tomato broth and a durum tube.

Incubated at 30°c for 2 days Observe durum tube for carbon dioxide production.

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Figure 1 Gannt Chart for Semester 2 67

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