Fats Flashcards

1
Q
Which of the following foods is an example of a monounsaturated fat source?
A) Butter
B) Steak
C) Fish
D) Olive
A

D) Olive

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2
Q
Which of the following groups is a good sources of polyunsaturated fatty acids?
A) Meat
B) Fruit 
C) Dairy products 
D) Most vegetable oils
A

D) Most vegetable oils

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3
Q

Describe three ways lipids differ from carbohydrates

A
  1. Lipids are not polymers
    lipids do not provide structure to food products
    lipids cannot be dissolved in water
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4
Q

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

A

Milk fat

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5
Q

30-40% palmitic, stearic

A

Animal fat

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6
Q

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

A

Marine oil

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7
Q

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

A

Oleic - Linoleic

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8
Q

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

A

Linolenic

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9
Q

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

A

False

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10
Q

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

A

Citric acid

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11
Q

Chelating agents are sometimes called __________

A

Sequestering agents

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12
Q

TRUE or FALSE?

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

A

FALSE

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13
Q

What is a plastic fat?

A

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

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14
Q

Why do same fats become rancid more quickly than others?

A

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

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15
Q

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

A

Cholesterol

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16
Q

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

17
Q

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

A

Coconut or palm

18
Q

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

19
Q

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

A

oil-in-water; water-in-oil

20
Q

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

21
Q

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

A

Cocoa butter

22
Q

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

A

Triglycerides

23
Q

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

24
Q

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

A
  • 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)
25
Fats differ from carbohydrates and proteins in that they are not _________ of repeating molecular units
Polymers
26
__________ acid is a common fatty acid found in butter
Butyric
27
Fatty acids differ in __________ and in the number of __________ atoms they contain
Length; hydrogen
28
The active ingredients in egg yolk stabilizing the emulsion are __________, the best known of which is __________
Phospholipids; lecithin
29
Fats can exist in more than one crystal form. This means that fats exhibit __________
Polymorphism
30
Two characteristics that lower the melting range of a fat include
1) Double bond (level of unsaturation) | 2) Short carbon chain
31
What are "plastic" fats?
Fat that are capable of being molded (butter, shortening)
32
__________ rancidity occur with acyl-glycerols are hydrolyzed to glycerol and free fatty acids
Hydrolytic
33
__________ is a process that removes the high melting triacylglycerols so that the oil will not solidify in the refrigerator
Winterization
34
"Synergists" used with antioxidants are more effective in preventing oxidation than either used alone. Citric acid is an effective synergist because it ...
binds with copper and iron which promote oxidation
35
What type of foods are subject to the development of rancidity?
Unsaturated fats and foods that don't have natural antioxidants
36
Name two natural and two synthetic antioxidants
NATURAL: Vitamin C and E SYNTHETIC: BHA and BHT
37
Define smoke point
Temperature at which fat starts to smoke
38
What factors decrease the smoke point of a fat?
1) Presence of free fatty acids | 2) Presence of mono- and di-glycerides
39
TRUE or FALSE? | The fat-smoke results from the change of glycerol to "acrolein" which is quite irritating to the eyes and nose
TRUE