Laboratory Manual: Fats and oils technology

LABORATORY MANUAL

FATS AND OILS TECHNOLOGY

FOOD TECHNOLOGY DEPARTMENT POLITEKNIK SULTAN HAJI AHMAD SHAH

LABORATORY MANUAL

FATS AND OILS TECHNOLOGY

TS. ZALEHA BINTI ISMAIL HASNOOR HAFZAN BINTI BAHARUM ZAIDA BINTI ZAKARIA

Politeknik Sultan Haji Ahmad Shah

Published by POLITEKNIK SULTAN HAJI AHMAD SHAH SEMAMBU 25350 KUANTAN Copyright ©2021, by Politeknik Sultan Haji Ahmad Shah Materials published in this book under the copyright of Politeknik Sultan Haji Ahmad Shah. All rights reserved. No part of this publication may be reproduced or distributed in any form or by means, electronic, mechanical, photocopying, recording, or otherwise or stored in a database or retrieval system without the prior written permission of the publishers.

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Acknowledgement We are very grateful to Allah SWT because with his permission this e-book is successfully produced. We would like to express our appreciation to Head of Food Technology Department and Head of DTM and DMH program for their support and encouragement in producing this e-book. Our gratitude also to family and friends who have been involved either directly or indirectly because without their support this e-book would not have been completed. .

Abstract Fats and oils Technology Laboratory Manual is written for students in the Diploma in Food Technology and Halal Management programme. This manual enhances the students’ knowledge regarding edible fats and oils analysis and closely related to the course syllabus.

Included in this manual are the procedures of analysis for determining physical and chemical properties of fats and oils. There are ten experiments related to topics discussed in the syllabus. Lecturer may vary the raw materials used, the method or other parameters in accordance with the lesson learning outcomes required. The methods described in this manual have been modified from various sources and may not necessarily be the same methods used by other institution. The students are guided with certain tables and chart to provide a clear insight of what they have learnt in the theory session. It is hope that students will have a good opportunity to enrich their generic skills as required in the Outcome Based Education (OBE) system, that fulfill the requirements of Malaysian Qualification Framework set by the Malaysian Qualification Agency (MQA).

Edited by Ts Zaleha binti Ismail Hasnoor Hafzan binti Baharum Zaida binti Zakaria

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CONTENTS

01

LABORATORY SAFETY RULES

20

DETERMINATION OF PEROXIDE VALUE

04

DETERMINATION OF PHYSICAL CHARACTERISTIC OF FATS AND OILS

23

DETERMINATION OF KREIS VALUE

08

DETERMINATION OF VOLATILE COMPOUND

26

DETERMINATION OF SOAP CONTENT

11

DETERMINATION OF SLIP MELTING POINT

31

PRODUCTION OF MAYONNAISE

14

DETERMINATION OF IODINE VALUE

33

PRODUCTION OF BAR SOAP

17

DETERMINATION OF SAPONIFICATION VALUE

36

REFERENCES

iii

Laboratory Safety Rules General Guidelines 1. Conduct yourself in a responsible manner at all times in the laboratory.

2. Follow all written and verbal instructions carefully. If you do not understand a direction or part of a procedure, ASK YOUR TEACHER BEFORE PROCEEDING WITH THE ACTIVITY. 3. Never work alone in the laboratory. No student may work in the lab without the presence of the teacher.

4. When first entering a lab, DO NOT TOUCHES ANY EQUIPMENT, CHEMICALS, OR OTHER MATERIALS IN THE LABORATORY AREA UNTIL YOU ARE INSTRUCTED TO DO SO. 5. Perform only those experiments authorized by your teacher. Carefully follow all instructions, both written and oral. Unauthorized experiments are not allowed.

6. DO NOT EAT FOOD, DRINK BEVERAGES, OR CHEW GUM IN THE LABORATORY. Do not use laboratory glassware as containers for food or beverages.

7. Be prepared for your work in the laboratory. Read all procedures thoroughly before entering the laboratory. Never fool around in the laboratory. HORSEPLAY, PRACTICAL JOKES, AND PRANKS ARE DANGEROUS AND PROHIBITED. 8. Always work in a well-ventilated area. .

9. Observe good housekeeping practices. WORK AREAS

SHOULD BE KEPT CLEAN AND TIDY AT ALL TIMES. 10. Be alert and proceed with caution at all times in the laboratory. Notify the teacher immediately of any unsafe conditions you observe.

11. Dispose of all chemical waste properly. Never mix chemicals in sink drains. Sinks are to be used only for water.

Check with your teacher for disposal of chemicals and solutions.

12. Labels and equipment instructions must be read carefully before use. Set up and use the equipment as directed by your teacher.

13. Keep hands away from face, eyes, mouth, and body while using chemicals or lab equipment. Wash your hands with soap and water after performing all experiments.

01

14. Experiments must be personally monitored at all times. Do not wander around the room, distract other students, startle other students or interfere with the laboratory experiments of others.

15. Know the locations and operating procedures of all safety equipment including: first aid kit(s), and fire extinguisher. Know where the fire alarm and the exits are located.

16. Know what to do if there is a fire drill during a laboratory period; containers must be closed, and any electrical equipment turned off.

Clothing

Handling Chemicals

17. Any time chemicals, heat, or glassware

24. All chemicals in the laboratory are to be

are used, students will wear safety goggles.

considered dangerous. Avoid handling

NO EXCEPTIONS TO THIS RULE!

chemicals with fingers. Always use a

18. Contact lenses may be not be worn in

tweezer. When making an observation, keep

the laboratory.

at least 1 foot away from the specimen. DO

19. Dress properly during a laboratory

NOT TASTE, OR SMELL ANY CHEMICALS.

activity. Long hair, dangling jewelry, and

25. Check the label on all chemical bottles

loose or baggy clothing are a hazard in the

twice before removing any of the contents.

laboratory. Long hair must be tied back, and

Take only as much chemical as you need.

dangling jewelry and baggy clothing must be

26. NEVER return unused chemicals to their

secured. Shoes must completely cover the

original container.

foot. No sandals allowed on lab days.

27. NEVER remove chemicals or other

20. A lab coat or smock should be worn

materials from the laboratory area.

during laboratory experiments.

Accidents and Injuries 21. Report any accident (spill, breakage, etc.) or injury (cut, burn, etc.) to the teacher immediately, no matter how trivial it seems.

Do not panic.

22. If you or your lab partner is hurt, immediately (and loudly) yell out the teacher's name to get the teacher's attention. Do not panic.

23. If a chemical should splash in your eye(s) or on your skin, immediately flush with running water for at least 20 minutes.

Immediately (and loudly) yell out the teacher's name to get the teacher's attention.

02

Handling Glassware and Equipment

Heating Substances 32. Do not operate a hot plate by yourself.

28. Never handle broken glass with

Take care that hair, clothing, and hands

your bare hands. Use a brush and

are a safe distance from the hot plate at

dustpan to clean up broken glass.

all times. Use of hot plate is only allowed

Place broken glass in the designated

in the presence of the teacher.

glass disposal container.

33. Heated glassware remain very hot for

29. Examine glassware before each

a long time. They should be set aside in a

use. Never use chipped, cracked, or

designated place to cool, and picked up

dirty glassware.

with caution. Use tongs or heat protective

30. If you do not understand how to

gloves if necessary.

use a piece of equipment, ASK THE

34. NEVER look into a container that is

TEACHER FOR HELP!

being heated.

31. Do not immerse hot glassware in

35. Do not place hot apparatus directly on

cold water. The glassware may

the laboratory desk. Always use an

shatter.

insulated pad. Allow plenty of time for hot apparatus to cool before touching it.

03

DETERMINATION OF PHYSICAL CHARACTERISTIC OF FATS AND OILS (REFRACTIVE INDEX, SPECIFIC GRAVITY AND COLOR) Lesson learning outcomes: At the end of this laboratory session, students will be able to 1) Use refractometer, Oleometer and Lovibond Tintometer 2) Determine and compare refractive index, specific gravity and color of different oils

A) REFRACTIVE INDEX

Definition: Refractive index is a ratio of the speed of light in a vacuum relative to that speed through a given medium. It can summarize as formula below:

Principle: Measurement of refractive index of the sample by means of a suitable refractometer.

Reagents: Diethyl ether Apparatus: Refractometer, water bath.

Procedure 1) Prepare the refractometer and calibrate it by following the maker’s instructions for using the instrument.

2) Adjust the temperature of the circulating liquid from the water bath to the required temperature.

3) Place a few drops of the sample between the prism of the refractometer in such a way that the space between the prism is completely filled.

4) Wait for 2 to 3 minutes to allow the fat to assume the temperature of the prism.

5) Read the refractive index.

04

B) SPECIFIC GRAVITY

Definition: Specific gravity is the ratio of the weight of a unit volume of an oil or fat at t oC to the weight of a unit volume of water at 25oC.

Principle: The operation the hydrometer is based on the Archimedes principle that a solid suspended in a fluid will be buoyed up by a force equal to the weight of the fluid displaced. Thus, the lower the density of the substance, the further the hydrometer will sink.

Apparatus: Hydrometer, measuring cylinder

Procedure: 1) Cooling the sample until temperature reach to 15oC. 2) Pour the sample into a measuring cylinder, keeping the material as free of bubbles as possible.

3) Slowly lower the appropriate hydrometer into the material and allow it to come to equilibrium.

4) The hydrometer must not be in contact with the sides or bottom of the cylinder.

5) Read the result at the bottom of the meniscus.

6) Record the reading as accurately as possible to the third decimal place.

05

C) COLOR

Definition: The color of a sample is the color in Lovibond units as measured on a Lovibond Tintometer

Principle: Matching of color of the light transmitted through a specified depth of liquid fat to the color of the light, originating from the same source, transmitted through standard color slide.

Procedure 1) Place the sample into cell.

2) Put the cell at the shelf.

3) Switch on the power supply.

4) Determine the color by achieving the best possible match with the standard color slides of red and yellow indices.

Discussions: 1. Which sample shows the lowest and highest results for each analysis? Explain the answer.

2. What is the importance of each analysis?

3. What are the factors affect the results

06

Result a. Refractive Index Refractive

Index

Sample

Reading 1 Reading 2 Reading 3 Average

b. Specific Gravity Specific

Gravity

Sample

Reading 1 Reading 2 Reading 3 Average

c. Color Color

Sample

White

Blue

Red

Yellow

07

DETERMINATION OF VOLATILE COMPOUND Lesson learning outcomes: At the end of this laboratory session, students will be able to 1) Set up apparatus according to procedure given in the manual 2) Determine and compare volatile compound in different samples of oils

Definition: Volatile compound is defined as the loss in weight of the oil when heated under the test conditions specified.

Principles: Heating of an oil sample in an oven at 103oC and followed by determination of the loss in weight of the oil.

Apparatus: Oven, aluminium dish, desiccators, analytical balance

Procedure: 1) Dry a clean aluminium dish and lid in the oven at 103 ± 2oC for at least 15 minutes and allow to cool in a dessiccator .

2) Weigh the dish and lid (W). Put 10g of the oil into the dish.

3) Weigh the dish and lid plus the oil (Wb).

4) Place the dish and lid in the oven at 103 ± 2 oC for exactly 1 hour (make sure the lid is remove during heating in oven) 5) Transfer the dish and lid and allow it to cool thoroughly in the desiccators (30-45 minutes) before reweighing.

6) Put the dish and lid into the oven again for 30 minutes and cool in desiccator before reweighing.

7) Repeat the (6) step until the constant weigh is obtained (Wd).

08

Calculation:

Volatile compound (%) = Wb-Wd Wb - W

x 100

W = weigh (g) of dish and lid Wb = weigh (g) of dish and lid + oil Wd = weigh (g) of dish and lid + oil after drying

Discussions: 1. Which sample shows the highest and lowest value? Explain the answer.

2. What is the importance of this analysis?

3. Name the types of volatile compounds in oil samples.

4. Explain the reaction occurred during heating process.

5. State a few precaution steps should be followed in this experiment

09

Results: a. Determination of Volatile compounds Sample

Reading

Weight of

Weight of dish

Weight of dish

dish (W)

and sample

and sample

(g)

(Wb)(g)

(Wd)(g)

Weight of

Weight of dish

dish (W)

and sample

Weight of dish and sample

(g)

(Wb)(g)

(Wd)(g)

Weight of

Weight of dish

Weight of dish

dish (W)

and sample

and sample

(g)

(Wb)(g)

(Wd)(g)

Calculation

Reading 1

Reading 2

Reading 3

Average

Sample

Reading

Calculation

Reading 1

Reading 2

Reading 3

Average

Sample

Reading

Reading 1

Reading 2

Reading 3

Average

b. Results of Volatile compounds Sample

Volatile

compounds

(%)

10

Calculation

DETERMINATION OF SLIP MELTING POINT Lesson learning outcomes: At the end of this laboratory session, students will be able to 1) Set up apparatus according to procedure given in the manual 2) Determine and compare melting point of different samples of oils

Definition: Slip melting point (slip point) is the temperature at which a column of fat rises in an open capillary tube under specific conditions of the test.

Principles: Immersion of a prepared capillary tube containing a column of the fat is immersed in a bath of water which is warmed at a specified rate until the melting point is reached.

Apparatus: Retort stand, capillary glass tube, beaker, hot plate, rubber band, thermometer, magnetic stirrer, chiller 11

Next, think of a compelling feature for your cover story. This will be Procedure: what draws your audience in.

a. Sample preparation 1) Melt the sample. Dip at least three clean capillary tubes into the completely liquid sample so that columns of fat about 1 cm high are obtained in tubes.

2) Chill the fat column by holding and rolling the ends of the tubes containing the sample pressed against a piece of ice until the fat has solidified.

3) Wipe the tubes against a piece of tissue paper as quickly as possible.

4) Place the tube in a beaker contains water that has been equilibrating at 10 oC. 5) Transfer the beaker into incubator (10 oC) for 16 hours. b. Analysis of sample 1) Remove the capillary tube from the test tube and attach with a rubber band to a thermometer such that the lower ends of the tubes are level with the bottom of the mercury bulb of the thermometer.

2) Suspend the thermometer in the beaker containing 800 ml of clear distilled water.

3) The bottom of the thermometer is immersed in the water to a depth of about 3 cm.

4) Agitate the water with a magnetic stirrer and apply heat so as to increase the temperature at a rate of 1 oC per minute.

5) Continue the heating until the fat column rises in each tube.

6) Observe the temperature of the water at which each column rises.

Discussions: 1. Which sample shows the highest and lowest value? Explain the answer.

2. What is the importance of this analysis?

3. Explain why do samples should be keep at lower temperature for at least 24 hours?

4. State the factors affect the melting points.

5. State a few precaution steps should be followed in this experiment.

12

Results: a. Melting point of fat samples Melting point

Sample

(oC)

Calculation of

average

Reading 1

Reading 2

Reading 3

Average Melting point

Sample

(oC)

Calculation of

average

Reading 1

Reading 2

Reading 3

Average Melting point

Sample

(oC)

Calculation of

average

Reading 1

Reading 2

Reading 3

Average Melting point

Sample

(oC) Reading 1

$550 Reading 2

Reading 3

Average

b. Results of Melting point Sample

Melting point (oC)

13

Calculation of

average

DETERMINATION OF IODINE VALUE Lesson learning outcomes: At the end of this laboratory session, students will be able to 1) Prepare the reagent 2) Set up apparatus according to procedure given in the manual 3) Determine and compare iodine value of different samples of oils

Definition: Iodine value is a measure of the unsaturation of fats and oils. It is expressed as the number of

Reagents:

grammes of iodine absorbed by 100 g of the fat

Cyclohexane, potassium iodide solution (10 %

under the test conditions used.

w/v), starch indicator solution (1% w/v), wij’s reagent, sodium thiosulphate (0.1 N), distilled

Principles:

water (should be free from dissolve oxygen by

Addition of a solution of iodine monochloride in a

boiling and cooling the water)

mixture of acetic acid and carbon tetrachloride to a test portion. Reduction of the excess of iodine monochloride after a specified reaction time by addition of potassium iodide solution and water, and followed by titration of the liberated iodine with standard volumetric sodium thiosulphate solution.s a measure of the unsaturation of fats and oils. It is expressed as the number of grammes of iodine absorbed by 100 g of the fat under the test conditions used.

Apparatus: Burette, conical flask, measuring cylinder, retort stand, pipette.

14

Procedure 1) Weigh 0.5 g sample in conical flask.

2) Add 20 ml of cyclohexane and 25 ml of the Wij’s reagent.

3) Shake gently and place the flask in the dark for 30 minutes at room temperature.

4) After standing add 20 ml of potassium iodide solution and 100 ml of distilled water.

5) Titrate with the sodium thiosulphate until the yellow color due to iodine has appeared.

6) Add 1 ml starch indicator solution and continue the titration until the blue color just disappears after very vigorous shaking.

7) Carry out a blank test simultaneously under the same conditions.

Calculation: Iodine value =

12.69 x N x (Vb -Vs) W

Vb = volume (ml) of sodium thiosulphate used for the blank Vs = volume (ml) of sodium thiosulphate used for the determination N = normality of sodium thiosulphate solution used W = weigh of sample

Discussions: 1. Which sample shows the highest and lowest value? Explain the answer.

2. What is the importance of this analysis?

3. What was the typical reaction involved in this test?

4. Explain why do samples should be keep in dark place for 30 minutes.

5. Why does blank titration shows the higher value compared to sample titration?

6. State a few precaution steps should be followed in this experiment.

15

Results: a. Determination of Iodine Value Blank

Volume of sodium thiosulphate (ml)

Calculation

Reading 1

Reading 2

Reading 3

Average Volume of sodium Weight of sample (g) Calculation thiosulphate (ml)

Sample Reading 1

Reading 2

Reading 3

Average

Volume of sodium Weight of sample (g) Calculation thiosulphate (ml)

Sample Reading 1

Reading 2

Reading 3

Average

Volume of sodium Weight of sample (g) Calculation thiosulphate (ml)

Sample Reading 1

Reading 2

Reading 3

Average

b. Results of Iodine Value Sample

Iodine value

16

DETERMINATION OF SAPONIFICATION VALUE Lesson learning outcomes: At the end of this laboratory session, students will be able to 1)Prepare the reagent 2)Set up apparatus according to procedure given in the manual 3)Determine and compare saponification value of different samples of oils

Introduction: Saponification value is the number of milligrams of potassium hydroxide required to saponify 1 g of fat under the condition specified. By measuring saponification value, mean molecular mass can be obtained.

Principles: Splitting of the glycerides present by alcoholic alkali and neutralization of the free fatty acids. Titration of excess alkali with hydrochloric acid in the presence of an indicator.

Reagents: Ethanolic potassium hydroxide solution (0.5 N), hydrochloric acid (0.5 N), phenoftalein indicator, boiling chips.

Apparatus: Round flask, reflux condenser, hot plate, burette, pipette

Procedure 1) Weigh 2.000 ± 0.005 g samples into conical flask.

2) Add 25 ml ethanolic potassium hydroxide solution and some boiling chips.

3) Connect the reflux condenser and boil gently for at least 1 hour.

4) Allow the flask to cool.

5) After completely cooling, add 1 ml of phenoftalein indicator and titrate with HCl 0.5 N until the pink color of the indicator just disappears.

6)Conduct a blank determination simultaneously with the test sample using the same procedure.

17

Calculation: Saponification value =

56.1 x N x (Vb-Vs) W

Vb = volume (ml) of HCl solution use for the blank Vs = volume(ml) of HCl solution use for the determination of the sample N = normality of HCl solution W = weigh of sample (g)

Discussions: 1. Which sample shows the highest and lowest value? Explain the answer.

2. What is the importance of this analysis?

3. State the typical reaction involved in this test.

4. What is the purpose of reflux process in this analysis?

5. State a few precaution steps should be followed in this experiment

18

Results: a. Determination of Saponification Value Blank

Volume of sodium thiosulphate (ml)

Calculation

Reading 1

Reading 2

Reading 3

Average Volume of sodium Weight of sample (g) Calculation thiosulphate (ml)

Sample Reading 1

Reading 2

Reading 3

Average

Volume of sodium Weight of sample (g) Calculation thiosulphate (ml)

Sample Reading 1

Reading 2

Reading 3

Average

Volume of sodium Weight of sample (g) Calculation thiosulphate (ml)

Sample Reading 1

Reading 2

Reading 3

Average

b. Results of Saponification Value Sample

Saponification value

19

DETERMINATION OF ACID VALUE Lesson learning outcomes: At the end of this laboratory session, students will be able to 1) Prepare the reagent 2) Set up apparatus according to procedure given in the manual 3) Determine and compare acid value of different samples of oils

Definition: Acid value is the number of milligrams of potassium hydroxide necessary to neutralize the free acids in 1 gram of sample. The acid number is a measure of the amount of carboxylic acid groups in a chemical compound such as a fatty acid.

Principles: Dissolution of fat of the fat in neutralized isopropanol and neutralization of the free fatty acids with standard alkali.

Reagents: a. Standard potassium hydroxide, KOH (0.1 N) (KOH approximately 0.1 N should be standardized with potassium hydrogen phthalate (KHP) 0.1 N). b. Potassium hydrogen phthalate (KHP) (0.1 N) c. Phenoftalein indicator d. Neutralized isopropanol / ethanol

Apparatus: Burette, conical flask, water bath, analytical balance, retort stand, dropper

20

Procedure: a) Standardization of KOH 1) Pipette 20ml of KHP into a conical flask.

2) Add 2-3 drops of phenolphatalein.

3) Titrate with potassium hydroxide to the first permanent pink color.

4) The color must persist for 30 seconds.

Calculation:

Normality of alkali (KOH) = Normality of KHP x Volume of KHP Volume of KOH b) Neutralization of isopropanol 1) Place 50 ml isopropanol in a flask and bring the solution into water bath.

2) Add about 0.5 ml of phenolphatalein and neutralize by addition of 0.1N potassium hydroxide till a faint, but permanent pink color is obtained. c) Determination of acid value 1) Weigh 20.0g ± 0.1g into a conical flask.

2) Add 50 ml of the neutralized isopropanol.

3)D Place E F Ithe N Iflask N Gonto water bath and regulate the temperature to about 40 oC. 4) Shake the sample gently while titrating with standard alkali to the first permanent pink color.

THE ISSUE 5) The color must persist for 30 seconds.

Calculation:

Free fatty acid (%) = 25.6 x N x V W

N = normality of KOH V = volume (ml) of KOH solution used W = weight (g) of the sample

Discussions: 1. Which sample shows the highest and lowest value? Explain the answer.

2. What is the importance of this analysis?

3. State the reaction of hydrolysis of triglycerides.

4. What are the factors affect the results?

5. State a few precaution steps should be followed in this experiment.

21

Results: a. Standardization of KOH Volume of KOH Calculation of Normality of KOH Reading 1 Reading 2 Reading 3 Average b. Determination of Acid Value

Sample

Volume of

KOH (ml)

Weight of

sample (g)

Calculation

Volume of

KOH (ml)

Weight of

sample (g)

Calculation

Volume of

KOH (ml)

Weight of

sample (g)

Calculation

Reading 1 Reading 2 Reading 3 Average Sample

DEFINING T H E I SSample SUE

Reading 1 Reading 2 Reading 3 Average

Reading 1 Reading 2 Reading 3 Average

N = normality of KOH V = volume (ml) of KOH solution used W = weight (g) of the sample

c. Results of Acid value Sample

Acid value

22

Definition: Peroxide value is a measure of those substance in a sample expressed in terms of miliequlivalents of active oxygen per kilogramme which oxidizes potassium iodide under the condition of the test.

DETERMINATION OF PEROXIDE VALUE

Principles: Treatment of a test portion in a solution of acetic acid and chloroform with a solution of potassium iodide. Peroxide substance can liberate the KI into free iodine. The free iodine is titrated with solution of sodium thiosulphate in the presence of starch indicator.

Lesson learning outcomes: At the end of this laboratory session, students will be able to

Reagents:

1) Prepare the reagent

Acetic acid – chloroform solution (mix 3 parts by volume of glacial acetic acid with 2 parts by volume of chloroform), saturated potassium iodide solution, sodium thiosulphate solution (0.01 N) and starch indicator.

2) Set up apparatus according to procedure given in the manual 3) Determine and compare peroxide value of different samples of oils

Apparatus: 23

Conical flask, burette, pipette and retort stand.

Procedure 1) Weigh 5.00 ± 0.05 g of the liquid sample into flask.

2) Add 30 ml acetic acid-chloroform solution.

3) Swirl the flask until the sample is dissolved in the solution.

4) Add 0.5 ml of saturated potassium iodide with a graduated pipette.

5) Swirl the solution for 1 minute and then add 30 ml distilled water.

6) Titrate with 0.01 N sodium thiosulphate solutions adding it gradually and with constant and vigorous shaking.

7) Continue the titration until the yellow color has almost disappeared.

8) Add 0.5 ml of starch indicator solution.

9) Continue the titration, shaking the flask vigorously near the end point to liberate all the iodine from the chloroform layers.

10) Add the thiosulphate solution until the blue color has just disappeared.

11) Carry out a blank test in parallel with the determination

Calculation: Peroxide value (Expressed in milliequivalents of activeoxygen perkilogramme of sample)

= (Vs –Vb) x N x 1000 W

N = Normality of sodium thiosulphate solution Vs = volume (ml) of sodium thiosulphate solution used for the determination Vb = volume (ml) of sodium thiosulphate solution used for the blank W = weigh of sample (g)

Discussions: 1. Which sample shows the highest and lowest value? Explain the answer.

2. Explain the stages of oxidation.

3. What is the importance of this analysis?

4. What are the factors affect the results?

5. State a few precaution steps should be followed in this experiment.

24

Results: a. Determination of Peroxide Value Volume of

Blank

Calculation

sodium

thiosulphat (ml) Reading 1

Reading 2

Reading 3

Average Volume of

Sample

sodium

Weight of

sample (g)

Calculation

Weight of

sample (g)

Calculation

Weight of

sample (g)

Calculation

thiosulphate (ml) Reading 1

Reading 2

Reading 3

Average Volume of

Sample

sodium

thiosulphate (ml)

Average Volume of

Sample

sodium

thiosulphate (ml) Reading 1

Reading 2

Reading 3

Average b. Results of Peroxide value Sample

Peroxide value

25

DETERMINATION OF KREIS VALUE Lesson learning outcomes: At the end of this laboratory session, students will be able to 1) Prepare the reagent 2) Set up apparatus according to procedure given in the manual 3) Determine and compare kreis value of different samples of oils

Definition: Kreis test has the advantage that it is rapid and also gives an indication of incipient rancidity.

In fact it has sometimes been criticized on this score. It was one of the first test uses to evaluate the oxidation of fat and involves the production of red color. A very faint red color does not necessarily denote rancidity but a color of up to 3 red units is considered to indicate incipient rancidity. If a color reading between 3 and 9 red units is obtained it is considered to indicate rancidity towards the end of the induction period. Color reading of over 8 red units is considered to indicate definite rancidity

Principles: The procedure involves measurement of a red color that is believed to result from reaction between oxidized fats or oils with phloroglucinol in acid condition. The compounds that responsible for the red color reaction are aldehyde and their acetals.

03

26

Reagents: Phloroglucinol (0.1% (w/v) in diethyl ether solution), concentrated hydrochloric acid.

Apparatus: Lovibond tintometer, glass cell, conical flask, pipette, beaker.

Procedure: 1) Place 10 ml sample in conical flask and add 10 ml 0.1 % phloroglucinol solution.

2) Then add 10 ml concentrated HCl and shake vigorously for about 30 seconds. (A red aqueous solution is obtained if the material is rancid).

3) Measure the red color using lovibond tintometer.

4) Report the results in red units.

Discussions: 1. Which sample shows the highest and lowest value? Explain the answer.

2. What is the importance of this analysis?

3. State the typical reaction involved in this test.

4. What are the factors affect the results?

5. State a few precaution steps should be followed in this experiment.

Results: Sample

Value of Red Unit

27

Observation of color

DETERMINATION OF SOAP CONTENT

Definition: The method determines soap as sodium palmitate in oils.

Principles: Volumetric titration of a sample solution with hydrochloric acid solution using bromophenol blue as an indicator.

Reagents: Lesson learning outcomes:

Acetone, hydrochloric acid (0.01 N),

At the end of this laboratory session, students will be able to 1) Prepare the reagent 2) Set up apparatus according to procedure given in the manual 3) Determine and compare soap content of different samples of oils

bromophenol blue indicator.

Procedure 1) Prepare the aqueous acetone solution by adding 0.5 ml of the bromophenol blue indicator to each 100 ml of the aqueous acetone just before use and titrating with 0.01 N HCl until it just yellow In color.

2) Weigh 40 g of the oil in conical flask.

3) Add 1 ml of distilled water, warm in water bath and shake the flask.

4) Add 50 ml of the acetone solution and shake vigorously.

5) Allow the contents to stands until they separate into two layers.

6) If soap is present the upper layer will be colored green to blue.

7) Then add 0.01 N HCl solution, until the yellow color of the upper layer turn to yellow.

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Apparatus: Conical flask, water bath, beaker, dropper.

Calculation:

sodium oleate (% w/w) = 0.304 x T W

T= volume (ml) of 0.01 N HCl solution W= weigh of sample (g)

Discussions: 1. Which sample shows the highest and lowest value? Explain the answer.

2. What is the importance of this analysis?

3. What is the effect if the value did not follow the standard?

4. What are the factors affect the results?

5. State a few precaution steps should be followed in this experiment

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Results: a. Determination of Soap content Volume of

Blank

Calculation

0.01N HCl

(ml) Reading 1

Reading 2

Reading 3

Average Sample

Volume of

Weight of

0.01N HCl

sample (g)

Calculation

(ml) Reading 1

Reading 2

Reading 3

Average Sample

Volume of

Weight of

0.01N HCl

sample (g)

Calculation

(ml) Reading 1

Reading 2

Reading 3

Average Sample

Volume of

Weight of

0.01N HCl

sample (g)

(ml) Reading 1

Reading 2

Reading 3

Average

b. Results of Soap Content Sample

Soap content

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Calculation

PRODUCTION OF MAYONNAISE

Lesson learning outcomes: At the end of this laboratory session, students will be able to 1) Prepare the ingredients 2) Set up apparatus according to procedure given in the manual 3) Produce mayonnaise according to the formulation 4) Detect the effects of the products

Definition: Mayonnaise is a stable emulsion of oil, and vinegar or lemon juice, with many options for embellishment with other herbs and spices. Egg yolk is the traditional emulsifier.

Ingredients: • egg yolks, at room temperature • 2-3 tea spoon fresh lemon juice Pinch of salt • 100ml olive oil • 100ml vegetable oil

Apparatus: Food processor, measuring jug 31

Procedure 1) Place the egg yolks, 2 tsp of the vinegar and a pinch of salt in the bowl of a food processor and process until the mixture just begins to thicken.

2) Pour the vegetable oil into a measuring jug.

3) With the motor running, gradually add oil to egg-yolk mixture in a thin steady stream, occasionally stopping to scrape down the side of the bowl with a spatula, until the mixture is thick, creamy and pale.

4) Add the oil slowly, but not too slowly as the mixture could thicken too quickly

Discussions: 1. State the function of each ingredient in mayonnaise.

2. Which formulation shows the best mayonnaise? Explain the answer.

3. Differentiate the color, texture and smell of the mayonnaise using sensory evaluation.

4. What are the factors affect the results?

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PRODUCTION OF BAR SOAP

Lesson learning outcomes: At the end of this laboratory session, students will be able to 1) Prepare the ingredients.

2) Set up apparatus according to procedure given in the manual.

3) Produce bar soap according to the formulation.

4) Detect the effects of the products.

Definition: Solid or bar soap, an anionic surface-active agent is a mixture of fatty acid salts with strong alkali especially NaOH or KOH. Soap can be prepared either through saponification reaction of NaOH and fats/oils, saponification of NaOH and fatty acid methyl ester, or neutralization of pure fatty acid with NaOH.

Principles: The soapmaking reaction is called saponification, and after reacting, the mixture is said to be saponified. Saponification involves reacting the fat or oil with a strong base, usually sodium hydroxide (also known as lye or caustic soda), although can also use potassium hydroxide (aka caustic potash). This reaction breaks the triglyceride into the glycerine and soap molecules.

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HOW TO PRODUCE SOAP?

Ingredients: • Sodium Hydroxide pellet, NaOH • Distilled water • Coconut oil • Palm Oil • Essential oil/ fragrance oil • Colorants

Apparatus: Beaker, Measuring Cylinder, Spatula, Thermometer, Soap mould/ Silicone mould, pH meter, Hot Plate

Procedure: A) Calculation of Lye OIL USE

% OIL

TOTAL OIL NEED

SAP INDEX*

AMOUNT OF LYE

Coconut oil

15%

15/100 x 1000 = 150

0.19

150g x 0.19 = 28.5g

Palm Oil

85%

85/100 x 1000 = 850

0.141

850g x 0.141 = 119.85g TOTAL : 148.35g

REDUCE LYE/ LYE DISCOUNT: 5% -8% (148.35 x 0.05 = 7.42 g)

TOTAL LYE NEED = (Total Lye – Lye Discount) 148.35 – 7.42= 140.93 g

AMOUT OF WATER : (*RATIO LYE : WATER, 1: 2.2 ) 140.93 x 2.2 = 310.05 ml

B) Calculation of Soap Hardness OIL USE

% OIL

TOTAL OIL

INS NUMBER*

SOAP HARDNESS

Coconut oil

15%

258

Palm Oil

85%

15/100 x 1000 = 150 85/100 x 1000 = 850 TOTAL : 1000g

150g / 1000 x 258 = 38.7 850g / 1000 x 145 = 123.25 TOTAL : 161.95

TOTAL: 100%

145

STANDARD HARDNESS OF SOAP = 135 - 165

* SAP INDEX: Saponification Index, Amount of Lye Use React With Oil * INS NUMBER: How Much Of Lye React With Oil (SAP-IV) * RATIO LYE: WATER, Follow Standard Soapmaker

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1) Dissolve sodium hydroxide pellets in distilled water (CAUTION: PLEASE HANDLE IN FUME CHAMBER). Put them aside and let them cool down (45-50 oC).

2) Heat the oil at 45-50 oC, then pour the sodium hydroxide solution (lye) into the oil.

Whisking the mixture until appear trace (This is when the oils and lye solution have emulsified).

3) Add essential oil and blend the oil.

4) After about 15 minutes, add colorant and fragrance to the mixture and stir gently.

5) Place the mixture of soap into a mould covered with grease paper and let it to cool down (At this stage, the soap is still caustic, so be sure to have your gloves on while handling it).

6) Test with pH meter to test the alkalinity.

7) After more than 24 hours, carefully remove the soap from the mould and slice into bars.

8) Once the soap has been cut into bars, set them aside for 3-4 weeks to dry and “cure”.

Discussions: 1. State the function of each ingredient in bar soap production.

2. What is the additive usually used in the preparation of bath soap?

3. Saponification reaction can take place without external heating. Explain how the internal heat can help this saponification process?

4. Explain the properties and their characteristics of making a good hard soap.

5. What is the importance of ‘superfatting’ in bar soap?

6. State a few precaution steps should be followed in this experiment.

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References 1. Official Methods and Recommended Practices of the AOCS, 7th Edition,2nd Printing, American Oil Chemists’ Society, ISBN: 978-1-630670-60-3 2. IUPAC (1987) Standard Methods for the Analysis of Oils, Fats and Derivatives 1st Supplement to the 7th Edition, OXFORD BLACKWELL SCIENTIFIC PUBLICATIONS, ISBN: 0-632-03337-I 3. MPOB Test Methods. (2004)”A Compendium of Test on Palm Oil Products, Palm Kernel Products, Fatty Acids, Food Related Products and Others”. Malaysian Palm Oil Board, Selangor.

4. FOSFA International Official Method 5. ISO 6321:2002 (2002) Animal and vegetable Fats and Oils -Determination of Melting Point in Open Capillary tubes (Slip point). International Organization for Standardization 6. Codex Alimentarius (2015) CODEX STAN 210-1999: Standard for Named Vegetable Oils.p.1-13 7. Shahidi, F. (2005). Bailey's Industrial Oil And Fat Products, Edible Oil And Fat Products: Products And Applications (Bailey's Industrial Oil & Fat Products) (Volume 4).

Wiley 8. Richard, D.O. (2004). Fats And Oils: Formulating And Processing For Application.

CRC Press.

9. Gunstone, F. D. (2004). The Chemistry Of Oils And Fats. Wiley.

10. Wolf, H. (2000). Edible Oil Processing. Sheffield Academic Press ; CRC Press.

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