Hillary was interested in making a whitesauce for a cheese souffle.

She had two fat mixtures to use and was not concerned about flavor

or

color in making her choice. Fat A was clarified purified butter

which

had not undergone any hydrolytic rancidity. Fat B was clarified

butter which had undergone a 5% hydrolysis of the triglycerides due

to

hydrolytic rancidity. What would you expect to be the influence

upon

the viscosity of the gelatinized starch paste? Explain your

answer.

What causes mayonnaise to thicken as it is prepared?

List changes in specific foods and their qualities of oil (or fat) was

soluble in water. Be specific.

What is the role(s) of lipids in: fruit, starch gelatinization,

frozen dessert crystallization, meat production/quality?

Mastery of the following reaction is not in itself of critical

importance; however, an understanding of it does serve to explain

certain phenomena which affect food quality.

Show the synthesis and hydrolysis of a triglyceride.

Show the synthesis and hydrolysis of a triglyceride relates

related to hydrolytic rancidity.

If one wishes to prepare a fat spread (spread for bread) to be used in

a desert survival program in California, which one of the

triglycerides would predominant?

Which of the fats would be most susceptible to rancidity as evidenced

by free radicals, hydroperoxides, aldehydes, and ketones?

Which of the lipids is likely the least "sensitive" (or prone) to

oxidative rancidity?

Which triglyceride would likely be incorporated in shortening to be

used as an emulsifier for a shortened cake?

Coconut oil is inexpensive and often used in commercial food products.

Coconut oil is a saturated fat. How can this be an oil and yet be

saturated?

What determines the melting point of a fat? Of what importance

is the melting point of a fat in food preparation?

If there were two isomers of triglycerides B, one having "hydrogen" in

CIS form and the other in the TRANS form, which would likely have the

higher melting point? Why?

What would be the most desirable characteristic to consider if you

were choosing a fat to make French salad dressing?

Hillary measured the iodine number of 2 fats which appeared to be

equally solid ?! One had a "high" number and the second had a "low"

number. Explain the probably reason(s) for the similarities and

differences.

What are some of the special treatments given to rendered animal fats

or crude vegetable oils to make them more desirable products for

certain purposes?

Discuss the process of hydrogenation and its' effect in fats and oils.

Why is it used?

Briefly discuss the process of interesterification and rearrangementand it's effect in

fats and oils. Why is it used?

Hillary got ready to use a special fat she had ordered. It was 100%

triglyceride and so she began to make a cake; but, it was hard to

aerate: first it was a solid, then a liquid, then it turned a solid

again. What would be the most appropriate explanation?

Hillary, from Northern California, went to the American Dietetic

Association meeting in California last October and met her friends

from Bangor, Maine and Houston, Texas. The discussion came up about a

new sweet chocolate product they all were using in their food service

as a snack. Hillary was really enthusiastic about the fantastic

product. Both her Maine friend and Texas friend said they were

surprised as they thought it was a lousy product. The Maine friend

said the crystals were so fine and small the texture was too hard;

yet, the Texas friend indicated that the same chocolate just had the

opposite problem. The texture was just like syrup due to the very

large crystal size. Explain the probably reason for this difference.

Also, indicate why these three food service managers got such a

different product when it left the factory as one identical product.

Discuss polymorphism of fats: occurrence, impact on fat

characteristics, impact on food quality,

Hillary measured the iodine number of two fats which appeared to be

equally solid. One had a "high" number and the second had a "low"

number. Explain the probably reason(s) for the similarities and

differences.

Hillary wanted to develop a "house dressing". She had a choice of

several oils and several thickening agents. Using data furnished in

Table 1 for melting point and iodine value, which fat would most

likely permit Hillary to make a "French-style house dressing.

Characteristics of fats and thickening agents.

FAT MELTING SMOKE IODINE THICKENING EMULSION

POINT. C POINT. C VALUE AGENT* STABILITY**

A 16 160 106 A 8.0

B 43 160 106 B 2.5

C 23 40 37 C 8.0

D -10 180 136 D 12.5

E 5 130 67 E 6.0

*Used in conjunction with Fat A only to form emulsions.

**Milliliters separation after shaking.

Hillary heard about fats which were polymorphic. A salesman told her

Fat A or B were the same lipid composition, just different polymorphic

forms of lipids. Which fat likely has the most fatty acids with trans

form of double bonds? Explain.

Discuss why bubbling hydrogen through a soybean oil will not serve as

an antioxidant acting agent for oxidative rancidity.

The four types of rancidity in fats are: absorption of odors, action

of microorganisms, action of enzymes (lipases), atmospheric oxidation.

Briefly define and show the reaction indicative of action of enzymes

(lipases).

What are the factors promoting rancidity and the products resulting?

What is oxidative rancidity? Diagram the free-radical chain mechanism

which has been proposed in oxidative rancidity.

Compare types of rancidity by completing the attached chart

Comparison

Hydrolytic

Oxidase

type of foods for which it is

the greatest problem

portion of fat molecules

reacting

most sensitive way to detect

end products of reaction

methods to inhibit the reaction

What tests might you use to differentiate between the reactions in

oxidative and hydrolytic rancidity?

Briefly define and show the reaction(s) of oxidative rancidity

(nonenzyme).

INITIATION

PROPOGATION

TERMINATION

List factors affecting autoxidation.

What is an emulsion? Discuss factors giving stability.

List factors used to increase emulsifications and/or emulsion

stability.

How can a "broken" emulsion be reformed?

What are emulsifying agents? What "qualities" should they have? How

do they function? What is the mechanism? List examples.

What is the influence of the interfacial tensions in an emulsion?

How do emulsifiers influence the type of emulsion (O/W, W/O)? Why?

Describe and discuss (diagram and words) the process of

oxidative rancidity

Describe how emulsions are formed and stabilized.

If there were two isomers of a triglyceride, one having the

"hydrogen" in CIS form and the other in the TRANS form, which

would likely have the higher melting point?

CIS or TRA

Explain your answer

What is a lipid? a fat? an oil?

What are the types of fat rancidity? For each: what are the

factors promoting this type of rancidity and the products resulting?

What are some of the special treatments given to rendered

animal fats or crude vegetable oils to make them more desirable

products for certain purposes?

What is an emulsion? Discuss factors giving stability.

With popular emphasis on the use of salad oils, what

modifications of conventional recipes are necessary to

substitute these for plastic fats?

DEFINE THE FOLLOWING

winterization or rearrangement

degumming or bleaching

hydrogenation

emulsions

What is the difference between a fat, a oil, a lipid?

What contributions do fats make in foods? Where do we use fat in

foods?

With popular emphasis on the use of salad oils, what modifications of

conventional recipes are necessary to substitute these for plastic

fats?

Complete the diagram below to show the synthesis and hydrolysis of a

triglyceride.

H O H O

| |

H-C-OH OH-C-(CH2)7CH=CH(CH2)7CH3 H-C- -C-

(CH2)7CH=CH(CH2)7CH3

| |

| O | O

| |

H-C-OH OH-C-(CH2)16CH3 ------->H-C- -C-(CH2)16CH3

| <------- |

| O | O

| |

H-C-OH OH-C-(CH2)7CH=CH(CH2)7CH3 H-C- -C-

(CH2)7CH=CH(CH2)7CH3

| |

H H

Mastery of the above reaction is not in itself of critical importance;

however, an understanding of it does serve to explain certain

phenomena which affect food quality.

Discuss in what way the previous diagram on the synthesis and

hydrolysis of a triglyceride relates to hydrolytic rancidity.

What is oxidative rancidity? What portion of the previous diagram

relates to oxidative rancidity?

Coconut oil is inexpensive and often used in commercial food products.

Coconut oil is a saturated fat. How can this be an oil and yet be

saturated?

What would be the most desirable characteristic to consider if you

were choosing a fat to make French salad dressing?

What is the major reason a salad dressing is called low calorie?

In mayonnaise, where would the following be found in the emulsion?

vinegar PHASE

oil a. dispersed phase

paprika b. continuous phase

emulsifying agent c. interface

mustard

Diagrams of chemical formulas of four selected triglycerides.

H O H O

| |

H-C-0-C-(CH2)16-CH3 H-C-0-C-(CH2)7CH=CH(CH2)7CH3

| O | O

H-C-O-C-(CH2)14CH3 H-C-O-C-(CH2)7CH=CH-CH2CH=CH(CH2)4CH3

| O | O

H-C-O-C-(CH2)7CH=CH(CH2)7CH3 H-C-O-C-(CH2)7CH=CHCH2CH=CH(CH2)4CH3

| |

H H

TRIGLYCERIDE A TRIGLYCERIDE B

H O H O

| |

H-C-O-C-(CH2)14CH3 H-C-O-C-(CH2)14CH3

| O | O

H-C-O-C-(CH2)10CH3 H-C-O-C-(CH2)14CH3

| O | O

H-C-O-C-(CH2)7CH=CHCH2CH=CH H-C-O-C-(CH2)7CH=CH(CH2)7CH3

|

(CH2)4CH3

TRIGLYCERIDE C TRIGLYCERIDE D

Using the "Diagrams of Chemical Formulas of Selected

Triglycerides" answer the following questions. AFter you select

your answer, write a very brief justification of your choice.

Which triglyceride likely has the lowest melting point?

Which triglyceride likely has the widest plastic range?

Which triglyceride likely has the narrowest plastic range?

Which fat is likely the most susceptible to changes brought

about by hydrogenation?

Is one of the triglycerides more susceptible to hydrolytic

rancidity than the others? Which, or why?

Is one of the triglycerides more susceptible to oxidative

rancidity than the others? Which or why?

Which triglyceride likely has the highest smoke point?

Which triglyceride most likely needs to be kept

refrigerated?

Which triglyceride is best to use in salad

dressing/mayonnaise preparation?

Which is best to use in deepfat frying?

Which is best to use to make a meally pastry?

Which triglyceride has the most pronounced odor?

Which triglycerides is most likely an oil?

Which triglyceride is the most effective emulsifying agent?

Which triglyceride most easy to maintain a foam dispersion?

Which triglyceride most flavor to a product?

If one wished to prepare a fat spread (spread for bread) to

be used in a desert survival program in California, which

one of the triglycerides would predominant?

What would be the influence of adding a monoglyceride to fat

D on smoke point?

Which triglyceride would likely be incorporated in shortening to

be used as an emulsifier for a shortened cake?

Which of the following triglycerides (fats) would be most firm at room

temperature 27C, 70F)?

a. tristearin (contains 18 carbon saturated fatty acids)

b. triolein (contains 16 carbon saturated fatty acids)

c. triliolein (contains 18 carbons and 2 double bonds in fatty

acids)

d. tributyrin (contains 4 carbon saturated fatty acids)

One day some butter melted and Hillary decided to cool it slowly.

Which of the following best describes this product? (Note: think of

the results in comparison of contrast of the melted butter rapidly

cooled).

a. This butter would likely have better plascitiy.

b. Cooling rate does not influence crystallinity in fats.

c. The dispersion would likely look more solid as opposed to

showing the crystals in oily oil dispersion.

d. The cooled butter likely would have large crystals dispersed

in an "oily" appearing medium.

a type of lipid consisting chemically of one molecule of glycerol

combined with three fatty acids

a. fatty acid

b. monoglyceride

c. phospholipid

d. sterol

e. triglyceride

deterioration of fats, usually by an oxidation process, resulting in

objectionable flavors and odors.

a. frying

b. hydrogenation

c. isomerization

d. rancidity

e. winterization

term used to describe a broad group of substances with similar

properties or characteristics of insolubility in water and a greasy

feel.

a. carbohydrate

b. cellulose

c. lipid

d. protein

a substance that stops unwanted oxidations

a. antioxidant

b. emulsifying agent

c. oxidant

d. rancidity

e.

Term to describe the ability of a fat to be molded or shaped.

a. emulsification

b. hydrogenation

c. plasticity

d. rancidity

e. winterization

Term for removal of triglycerides with high melting points from oil to

be used as salad oil

a. emulsification

b. hydrogenation

c. plasticity

d. rancidity

e. winterization

Term for process to change liquid oils to solid or pliable

shortenings.

a. emulsification

b. hydrogenation

c. plasticity

d. rancidity

e. winterization

Term for deterioration of fats resulting in objectionable odor or

flavor.

a. emulsification

b. hydrogenation

c. plasticity

d. rancidity

e. winterization

A fatty acid with no double bonds between carbon atoms; it holds all

of the hydrogen that can be attached to the carbon atoms

a. linolenic acid

b. linoleic acid

c. saturated fatty acid

d. oleic acid

e. unsaturated fatty acid

A type of lipid consisting chemically of one molecule of glycerol

combined with three fatty acids

a. fatty acid

b. monoglyceride

c. phospholipid

d. sterol

e. triglyceride

Which of the following triglycerides (fats) would be most firm at room

temperature 27C, 70F)?

a. tristearin (contains 18 carbon saturated fatty acids)

b. triolein (contains 16 carbon saturated fatty acids)

c. triliolein (contains 18 carbons and 2 double bonds in fatty

acids)

d. tributyrin (contains 4 carbon saturated fatty acids)

The characteristics of the fatty acid is very important as generally a

triglyceride containing fatty acids of equal length but more of the

fatty acids are saturated than unsaturated would be (as opposed to the

reverse situation)

a. more likely to be a liquid at room temperature and be more

soluble and more polar in liquid (water) dispersions.

b. more likely to be a solid at room temperature and be less

polar and less soluble in liquid (water) dispersions.

c. more likely to be a liquid at room temperature and be less

soluble and less polar in liquid (water ) dispersions.

d. more likely to be a solid at room temperature and be more

polar and more soluble in liquid (water) dispersions.

One day some butter melted and Hillary decided to cool it slowly.

Which of the following best describes this product? (Note: think of

the results in comparison of contrast of the melted butter rapidly

cooled).

a. This butter would likely have better plasticitiy.

b. Cooling rate does not influence crystallinity in fats.

c. The dispersion would likely look more solid as opposed to

showing the crystals in oily oil dispersion.

d. The cooled butter likely would have large crystals dispersed

in an "oily" appearing medium.

From the listing on the right hand column, indicate how these

ingredients and procedures affect mayonnaise formation.

EMULSION FORMATION

Refrigerator temperature salad oil. a. Promote emulsion formation

Egg yolk. b. Inhibit emulsion formation

Wide, flat bottom bowl. c. No appreciable influence

Stirring with a spoon rather than on emulsion formation

beating with a beater.

Lemon juice used rather than vinegar.

Previously made mayonnaise is added

to the egg yolk/vinegar mixture.

In mayonnaise, where would the following be found in the

emulsion?

vinegar a. dispersed phase

oil b. continuous phase

paprika c. interface

emulsifying agent

Which is a fatty acid with no double bonds between carbon atoms;

it holds all of the hydrogen that can be attached to the carbon

atoms

a. butyric acid

b. caproic acid

c. saturated fatty acid

d. stearic acid

e. unsaturated fatty acid

Check each substance which may be used in food products to act as

an emulsifier.

a. dry mustard d. oil

b. water e. paprika

c. egg yolk f. lemon juice

The process of adding hydrogen at the double bond of selected

unsaturated fatty acids to make a more plastic fat is:

a. rearrangement

b. winterizing

c. emulsification

d. hydrogenation

What are the differences in stability between saturated and

unsaturated fats?

A plastic fat with emulsifiers added is better than one without

for use in which of the following products?

What is the definition of hydrogenated fat?

Differences in stability between saturated and unsaturated fats

include what characteristics?

Which of the following triglycerides (fats) would be most firm at

room temperature 27À$ÀC, 70À$ÀF)?

a. Tristearin (contains 18 carbon saturated fatty acids)

b. Triolein (contains 16 carbon saturated fatty acids)

c. Trilinolein (contains 18 carbons and 2 double bonds in fatty

acids)

d. Tributyrin (contains 4 carbon saturated fatty acids)

Which of the following most accurately reflects triglycerides

role in fats?

a. Triglycerides make up fats and permits the accurate

prediction of the characteristics of the fats.

b. Triglycerides are organic compounds which are

occasionally found in fats; but, fats are really only

made up of lipids.

c. Fats are complex ingredients made up of many component

parts so there is just no way to find out the

characteristics of the fats.

What is a common fat, which in composition is only 80% fat?

Processing the two terms at the left, indicate the correct type

of rancidity that would occur for each situation.

A. oxidative rancidity triglyceride is split to

glycerol and

B. hydrolytic rancidity free fatty acid

presence of lipase

an oxygen interceptor

(antioxidant

helps prevent this

saturated fatty acids

involved

Define and indicate the three major catagories of lipids.

Why are simple and mixed glycerides important?

Which of the following most accurately reflects triglycerides

role in fats?

a. triglycerides make up fats and permits the accurate

prediction of the characteristics of the fats.

b. triglycerides are organic compounds which are

occasionally found in fats; but, fats are really only made

up of lipids.

c. fats are complex ingredients made up of many component

parts so there is just no way to find out the

characteristics of the fats.

Define the following:

refined fats and oils used in food preparation, including

edible oils, margarine, butter, lard, and shortenings

a chemical molecule consisting of carbon and hydrogen atoms

bonded in a chainlike structure; combined through its acid

group (-COOH) with the alcohol glycerol to form

triglycerides.

temperature at which a solid fat becomes a liquid oil

ability to be molded or shaped; in plastic fats, both solid

crystals and liquid oil are present

describing substances that cannot be mixed or blended

an enzyme that activates hydrolytic rancidity in a

triglyceride

amount of oil required by USDA to label a permanent emulsion

mayonnaise

deterioration of fats, usually by an oxidation process,

resulting in objectionable flavors and odors.

The process of adding hydrogen at the double bond of

selected unsaturated fatty acids to make a more plastic fat

Indicate whether the following statements are true or false.

saturated fats are not susceptible to any rancidity

unsaturated fats are a liquid so rancidity is not a problem

antioxidants must be added to any saturated fat to prevent

rancidity

unsaturated fats are more readily susceptible to a common

type of oxidative rancidity

Fats should be stored best stored in which of the following

a. in a warm place

b. no longer than one week

c. in a dark air-tight container

d. in the pan used for deep fat frying

Check each substance which may be used in food products to act as

an emulsifier.

dry mustard oil

water paprika

egg yolk lemon juice