Fats

Question 1

Which of the following foods is an example of a monounsaturated fat source?
A) Butter
B) Steak
C) Fish
D) Olive

Answer 1

D) Olive

Question 2

Which of the following groups is a good sources of polyunsaturated fatty acids?
A) Meat
B) Fruit 
C) Dairy products 
D) Most vegetable oils

Answer 2

D) Most vegetable oils

Question 3

Describe three ways lipids differ from carbohydrates

Answer 3

1. Lipids are not polymers
   lipids do not provide structure to food products
   lipids cannot be dissolved in water

Question 4

30-40% oleic, 25-32% palmitic, 10-15% stearic, 3-5% butyric

Answer 4

Milk fat

Question 5

30-40% palmitic, stearic

Answer 5

Animal fat

Question 6

High in long chain polyunsaturated F.A., vitamin A and D

Answer 6

Marine oil

Question 7

Vegetable fats only, < 20% sat. fat, cotton seed, corn, peanut. olive safflower

Answer 7

Oleic - Linoleic

Question 8

High in linolenic, considerable oleic, linoleic, soybeans, wheat germ

Answer 8

Linolenic

Question 9

TRUE or FALSE?
The smoke point of a fat is the temperature at which smoke comes from the surface of the fat when heated. Thus, a fat with lower smoke point is more suitable for frying than a fat with higher smoke point

Answer 9

False

Question 10

Metals such as iron and copper may be present in trace amount in foods and will encourage the development of oxidative rancidity. Some synergists such as __________ bind or chelate metals and prevent metals from catalyzing the oxidation process

Answer 10

Citric acid

Question 11

Chelating agents are sometimes called __________

Answer 11

Sequestering agents

Question 12

TRUE or FALSE?

A winterized oil, usually called salad oil, has a HIGHER melting point, and does not crystallize in refrigerator

Answer 12

FALSE

Question 13

What is a plastic fat?

Answer 13

Fat that can be molded or pressed into various shapes without breaking (e.g., shortening, butter or margarine)

Question 14

Why do same fats become rancid more quickly than others?

Answer 14

A) Degree of saturation (more unsaturated, more rancidity)
B) Presence of free fatty acids through “clipping action” of the fatty acid from the glycerol which is caused by: light, heat, moisture, metals or enzymes

Question 15

Nutritional concerns centre around animal fats, which are highly saturated and contain __________

Answer 15

Cholesterol

Question 16

Oils used for salad oil should have HIGH/LOW melting point

Answer 16

Low

Question 17

__________ or __________ oil is used in crackers, where stability to oxidation over a long storage period is vital

Answer 17

Coconut or palm

Question 18

The solvent extraction process uses __________ to dissolve the oil from the oilseed flakes

Answer 18

Hexane

Question 19

Mayonnaise is an oil-in-water emulsion. Peanut butter is a(n) __________ emulsion. Margarine is a(n) __________ emulsion

Answer 19

oil-in-water; water-in-oil

Question 20

Biological catalysts, such as __________, can be used in interesterification reactions

Answer 20

Lipase

Question 21

__________ is characterized by a sharp melting transition close to body temperature (32-35 degrees Celsius)

Answer 21

Cocoa butter

Question 22

Quantitatively, the most important food lipids are mono- / di- or triglycerides

Answer 22

Triglycerides

Question 23

Smoking point is dependent upon the level of free fatty acids in the oil; the higher the free fatty acid levels, the __________ the smoke point

Answer 23

Lower

Question 24

There are many important roles of lipids in foods. For example, …..

Answer 24

• Carry fat soluble vitamin (A, D, E, K)
• Act as tenderizer in baked products
• Enhance flavour, texture
• Contribute to juiciness of steak
• Act as cooking medium (can be heated to high temperature)
• Provide feeling of satiety (satisfaction)

Question 25

Fats differ from carbohydrates and proteins in that they are not _________ of repeating molecular units

Answer 25

Polymers

Question 26

__________ acid is a common fatty acid found in butter

Answer 26

Butyric

Question 27

Fatty acids differ in __________ and in the number of __________ atoms they contain

Answer 27

Length; hydrogen

Question 28

The active ingredients in egg yolk stabilizing the emulsion are __________, the best known of which is __________

Answer 28

Phospholipids; lecithin

Question 29

Fats can exist in more than one crystal form. This means that fats exhibit __________

Answer 29

Polymorphism

Question 30

Two characteristics that lower the melting range of a fat include

Answer 30

1) Double bond (level of unsaturation)

2) Short carbon chain

Question 31

What are “plastic” fats?

Answer 31

Fat that are capable of being molded (butter, shortening)

Question 32

__________ rancidity occur with acyl-glycerols are hydrolyzed to glycerol and free fatty acids

Answer 32

Hydrolytic

Question 33

__________ is a process that removes the high melting triacylglycerols so that the oil will not solidify in the refrigerator

Answer 33

Winterization

Question 34

“Synergists” used with antioxidants are more effective in preventing oxidation than either used alone. Citric acid is an effective synergist because it …

Answer 34

binds with copper and iron which promote oxidation

Question 35

What type of foods are subject to the development of rancidity?

Answer 35

Unsaturated fats and foods that don’t have natural antioxidants

Question 36

Name two natural and two synthetic antioxidants

Answer 36

NATURAL: Vitamin C and E

SYNTHETIC: BHA and BHT

Question 37

Define smoke point

Answer 37

Temperature at which fat starts to smoke

Question 38

What factors decrease the smoke point of a fat?

Answer 38

1) Presence of free fatty acids

2) Presence of mono- and di-glycerides

Question 39

TRUE or FALSE?

The fat-smoke results from the change of glycerol to “acrolein” which is quite irritating to the eyes and nose

Answer 39

TRUE