University of Minho Institute for Biotechnology and Bioengineering Centre for Biological Engineering
Necessidades e oportunidades de investigação no sector lácteo Dairy research – opportunities and needs J. A. Teixeira jateixeira@deb.uminho.pt
Dairy workshop Lugo, 26 October 2010
Universidade do MINHO
Braga Guimar達es
Introduction Overview Consumer demands for more convenient and varied milk products Extended shelf‐life of milk and milk products Healthier foods Sustainable and clean processes
Introduction Severity of the traditional processing food processing technologies
Development of thermal and non‐thermal technological approaches capable of substituting the traditional well established preservation processes.
Production of high volume effluents
Development of process for valorization of the effluents
Introduction Novel and emergent thermal technologies have been developed and can replace the traditional heating methods that rely on conductive and convective heat transfer •
• • • •
Dielectric heating • Radio frequency • Microwave heating Ohmic heating High pressure Pulsed electric fields New packaging systems
Ohmic Heating Ohmic heating
Why ? : • Heat is generated directly inside the food and this has direct implications in terms of both energetic and heating efficiency
Ohmic Heating Limit of the heating volume
SOLID PARTICLE Mass transfer (diffusion)
Heat transfer (cond./conv.) Flow eventually entering the ohmic heater (zero, if in batch operation)
Internal heat gen. Mass transf. (diff.) Heat transf. (cond.) Internal heat gen. Mass transf. (conv.) Heat transf. (conv.)
Momentum transfer
LIQUID PHASE Heat transfer (cond./conv.) Electrodes
Flow eventually leaving the ohmic heater (zero, if in batch operation)
Ohmic Heating 60 kW continuous ohmic heater (pilot‐scale)
Pilot‐scale continuous ohmic heater
Ohmic Heating Overall the major benefits claimed for ohmic heating technology are as follows: Temperature required for HTST processes can be achieved very quickly; Suitable for continuous processing without heat transfer surfaces; Uniform heating of milk with faster heating rates; Electric fields may provide a non‐thermal killing effect over some microorganisms, reducing the time for their inactivation Reduced problems with of overheating of the product compared to conventional heating; No residual heat transfer after the current is shut off, and very low heat losses; Low maintenance costs (no moving parts) and high energy conversion efficiencies; Environmentally friendly system.
Ohmic Heating Applications: Possible applications include most of the heat treatments such as blanching, evaporation, dehydration ,fermentation as well as pasteurization and sterilization. Processing of low‐acid particulate product in a can and pasteurized liquid egg Innovative applications, such as fruit puree Meat cooking Milk pasteurization
Ohmic Heating Microbial Inactivation Time to reduce 90 % of a microbial population (D values) is faster when ohmic heating is applied;
Effects on Enzymes Presence of an moderate electric does not cause an enhanced inactivation of Alkaline Phosphatase (ALP) and β-Galactosidase (β-GAL).
Effects on Milk Lipids Ohmic HTST pasteurization does not promote modification of Free Fatty Acids (off-flavour) in goat milk, when compared with conventional HTST pasteurization; Composition of fat was not altered by the presence of electric fields during ohmic heating.
Ohmic Heating Effects on Proteins Less protein denaturation → problems associated with heat transfer surfaces are eliminated (volumetric heating) Non‐thermal effects: presence of electric fields can promote conformational disturbances on tertiary protein structure (due to rearrangement of hydrogen bonds, hydrophobic interactions, and ionic bonds) Less association or aggregation of milk proteins
Important consequences on the acid‐induced gelation properties of milk
Ohmic Heating • Research is required in the following areas: •
To elucidate on the relative importance of electric current properties and the corresponding temperature values on the killing of microbes and in particular resistant structures (e.g., spores).
•
To characterize the effect of OH on the nutritive, organoleptic, and functional properties of dairy foods.
•
To develop methods that will allow for a more precise mapping of temperatures on foods submitted to OH.
•
To develop models that can adequately describe ohmic processing of foods.
•
To implement these models so that an adequate control of the rate ofheating can be achieved, thus minimizing the thermal degradation effects on desirable product attributes but maintaining a safe product
High Hydrostatic Pressure Non‐thermal approaches to milk processing may be also valuable alternative to the thermal processing: High Hydrostatic Pressure
Why ? : • Ability to inactivate microorganisms at near‐ambient temperatures, avoiding the undesirable effects of heat on the organoleptic properties of foods. • Maintenance of sensorial and nutritional properties of the products
High Hydrostatic Pressure High pressure in food processing High Hydrostatic Pressure (HHP) Novel non‐thermal processing technology Hydrostatic pressure (between 100‐600 MPa) is applied to the food at room temperatures;
High Hydrostatic Pressure Advantages of the use of HHP in food processing Applied pressure is transmitted instantaneously and homogeneously into the food, regardless of its shape and geometry The minimum processing using no additives allows the obtention of higher nutritional and organoleptic quality foods, with a better texture and improved shelf life High pressure systems have a wide application in other industries – they just need to be “transferred” to the food industry
High Hydrostatic Pressure • Japan was the first country where High Pressure processed foods were produced and sold, namely jams, fruit yoghurts, sauces and lemon juice • Nowadays, there is a wide range of HPP processed products – meat products, fruit juices & smoothies, seafood, dairy products, RTE meals,… • These products are targeted as high quality and high price
High Hydrostatic Pressure Applications in dairy products • Yogurt • Inactivation of yeast and moulds • Reduction of Lactobacillus number • Inactivation of contamination and acidification bacteria (survival of probiotics starins)
• Cheese • Enhanced maturation and elimination of pathogenic bacteria • Increase cheese yield
• Milk • Improved shelf life and improved properties of products made with HPP processed milk
High Hydrostatic Pressure High pressure in food processing Applications in dairy products Milk Processing
HPP is considered an interesting alternative for milk heat pasteurization and sterilization
Microoganism and certain enzymes are inactivated: Due to absence of heat, fresh flavor, color, taste and vitamins are minimally affected
Edible coatings and films Environmental impact Shelf-life extension
Consumer demand for ready-prepared foods
Edible coating
Consumer Health and Safety
Control migration of O2, CO2, H2O, aromas and/or lipids Carry active compounds (antimicrobials, antioxidants) Improve appearance Materials used: Polysaccharides (starch, cellulose, chitosan); Proteins (milk, soy); Lipids (waxes, oil)
Edible coatings and films
Relevant Coating and films properties •
Wetability,
•
Water vapour permeability,
•
O2 and CO2 permeability,
•
Solubility in water,
•
Colour – opacity and L*a*b*
•
Thermal analysis (DSC and TGA),
•
Mechanical analysis – tensile streght, elongation-at-break and Young’s modulus (Instron).
Edible coatings and films Cheese Applications •
Cheese with coating has a lower gas transfer rates as well as a decrease of the relative weight loss (ca. 8‐fold less the value in the absence of coating).
O2 and CO2 transfer rates in cheese at 21.86 ± 0.76 °C. Cerqueira et al. (2009). J. Agric. Food Chem. 57, 1456–1462
Edible coatings and films Cheese Applications •
Visual evaluation also confirmed that the uncoated cheese suffered from an extensive mold growth when compared with the coated cheese.
(a) Cheese with coating (a) and without coating (b).
Cerqueira et al. (2009). J. Agric. Food Chem. 57, 1456–1462
(b)
Edible coatings and films Cheese Applications Incorporation of antimicrobial agent • •
Extend product shelf-life Reduce the risk of pathogen growth on food surface
A
B
C
D
Inhibition of A. niger with chitosan‐natamycin coating. Cheese uncoated (A) and coated with chitosan containing natamycin 0.125 mg∙mL‐1 (B), 0.25 mg∙mL‐1 (C) and 0.50 mg∙mL‐1 (D). 1
Fajardo et al. (2010). Journal of Food Engineering 101, 349–356.
Edible coatings and films Incorporation of antimicrobial agent •
Potential application of nisin-coated films onto cheese in order to overcome the problems associated with post-process contamination of Listeria monocytogenes
•
The addition of nisin to galactomannan films is a viable alternative to reduced microbial growth, reduce water loss and increase ricotta cheese shelf-life. 8 7 6
log CFU/g
Nisin-added coating prevented the growth of L. monocytogenes during 21 days
5 4
Control Coating (no nisin‐added) Coating with nisin
3 2 1 0 0
2
Martins et al. (2010). J. Agric. Food Chem. 58, 1884–1891.
7
14
Storage time (days)
21
28
Lactose free products Lactose intolerance is the inability to metabolize lactose, because of a lack of the required enzyme lactase in the digestive system. It is estimated that 75% of adults worldwide show some decrease in lactase activity during adulthood
Global map of lactose intolerance frequencies
Lactose free products Solutions for lactose intolerance Consume lactose-free and lactose-reduced milk and milk products Lactose hydrolysis by the addition of lactase (galactosidase Development of efficient system for lactose hydrolysis (use of immobilized lactase) Development of low lactose content dairy products
Probiotic dairy products
Probiotics are live microrganisms thought to be healthy for the host organism. According to the currently adopted definition by FAO/WHO, probiotics are: "Live microorganisms which when administered in adequate amounts confer a health benefit on the host". Lactic acid bacteria (LAB) and bifidobacteria are the most common types of microbes used as probiotics; but certain yeasts and bacilli may also be helpful. Probiotics are commonly consumed as part of fermented foods with specially added active live cultures; such as in yogurt, soy yogurt or as dietary supplements. Probiotics are able to survive in the product and become active when entering the consumer’s gastrointestinal tract
Probiotic dairy products Factors to be considered in the development of probiotic dairy products the physiologic state of the probiotic selection/identification of new probiotic strains the physical conditions of product storage (eg, temperature) the chemical composition of the product to which the probiotics are added (eg, acidity, available carbohydrate content, nitrogen sources, mineral content, water activity, and oxygen content) development of techniques to enhance the survival of probiotic bacteria interactions of the probiotics with the starter cultures (eg, bacteriocin production, antagonism, and synergism) understanding of probiotic health benefits.
Cheese whey valorization
Cheese whey MILK
Casein (80%)
Whey (20%)
s1-casein
-lactoglobulin (50%)
s2-casein
-lactalbumin (20%)
-casein
Bovine albumin serum (10%)
-casein
Immunoglobulins (10%) Minor proteins (10%) (e.g. LF, LP, PP, OPN, GMP)
Cheese whey Gram/L
Microgram/L
Major proteins
Enzymes
Vitamins
Hormones
Milk fat
Whey
Non proteic nitrogen
Growth factors
Amino acids
Lactose
Minor proteins Bioactive peptides
Ultra-residual elements Residual elements Miligram/L
Main minerals
Nanogram/L
Cheese whey
Cheese whey
Cheese whey Cheese whey proteins - Market growth rates
Source – 3A Business Consulting
Cheese whey
Cheese whey
Cheese whey Whey to bioethanol… 8 million tons of lactose (worldwide annual whey production)
~50% not transformed into added‐value sub‐products
~2.3 million m3 ethanol
~3.5% of the 2008 world production
considering a 85% conversion yield
Worldwide production of bioethanol for fuel in 2008: ~65 million m3 Biotechnol Adv (2010) 28: 375-384
Cheese whey Whey to Ethanol Industrial Plants Ireland
Carbery Milk Products
since 1978, potable ethanol & ethanol for fuel (since 2005) 11 000 tons ethanol /year New Zealand
Fonterra
Anchor Ethanol (Fonterra subsidiary) potable ethanol & ethanol for fuel (since 2007) 17 million liters ethanol /year United States
Golden Cheese Land O’Lakes
Germany
Müllermilch
near Dresden; 10 million litres ethanol /year from dairy by-products
Cheese whey
Cheese whey Lactose as a source of prebiotics Prebiotics - “selectively fermented ingredients that allow specific changes, both in the composition and/or activity in the gastrointestinal microbiota that confers benefits upon host well-being and health”
Resistance to the upper gut tract Fermentation by intestinal microbiota
Classification criteria
Beneficial to the host health Selective stimulation of probiotics Stability to food processing treatments
Cheese whey Method
Ash Moisture Protein Saccharides Monosaccharides Disaccharides Oligosaccharides Trisaccharides Tetrasaccharides Pentasaccharides
AOAC 31.013 AOAC 925.45 Kjeldahl HPLC
% (p/p) 0.02 1.12 0.15 99.5 2.2 4.1 94.0 41.8 41.6 10.5
rsd 4.2 24.2 6.2 3.6 4.9 25.9 1.7 2.5 1.9 3.5
•Fermentation process – high yields and productivity; •Purified GOS are pure with ~99.5% of saccharides and ~94.0% of oligosaccharides; •GOS are stable under severe gastric and duodenal conditions •The PI score of the GOS sample is relatively high.
Universidade do MINHO
Braga Guimar達es
Thank you for your attention !