Topic 5: Part C Flashcards Preview

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Flashcards in Topic 5: Part C Deck (27)
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1
Q

Winterization of fats

A

process to produce salad oils that do not crystallize (cloudy) at refrigerator temps

2
Q

Oils can become cloudy at lower temps because ..

A

some of the triglyceride molecules crystallize and become solid

3
Q

Winterization of fats involved lowering the ..

A

temp of oil too a point at which the triglycerides with high melting points crystallize

4
Q

The oil is filtered to remove the crystals the ..

A

the reaming oil has a lower melting point and does not crystallize at refrigerator temp

5
Q

The chemical spoilage that commonly occurs with fats and fatty foods is called

A

rancidity

6
Q

Highly unsaturated fats/oils such as polyunsaturated fats are much more..

A

susceptible than saturated or monounsaturated fats (nuts, wheat germ, whole wheat flour highly susceptible)

7
Q

2 types of rancidity

A
  • oxidative rancidity

- hydrolytic rancidity

8
Q

Oxidative rancidity

A

occurs primarily with unsaturated fatty acid portions of triglycerides that are susceptible to oxidative changes. often results from a self-perpetuating chemical chain reaction.

9
Q

Oxidative reaction begins with the ..

A

addition of oxygen to carbon atoms next to a double bond in a fatty acid. The reaction results in formation of hydro peroxide.

10
Q

During oxidative reactions, Hydroperoxide molecules readily breakdown into..

A

volatile products that have off odours and flavours characteristic of rancid fat.

11
Q

Oxidative damage can be ..

A

prevented or slowed down through use of antioxidants

12
Q

Hydrolytic rancidity

A

involves breaking of chemical bonds and in the process the addition of water. result of the breaking of triglycerides structure composed of short chain FA. Results in the production of glycerol and free short chain fatty acids such as butyric acid and caproic acid.


13
Q

Importance of fats/oils in foods

A
  1. Source of essential fatty acids.
  2. Source of energy supply.
  3. Supply fat soluble vitamins. (A, D, E, K)

  4. Increase palatability of our food by enhancing the sensory properties (taste, flavour and texture).
  5. Increase the satiety value of a meal (full feeling) because fat moves very slowly in the gastrointestinal tract.
14
Q

Fat replacers

A

Products or ingredients that can replace part or all of the functions of fat in foods, and may/may not provide energy.

15
Q

It is difficult to find a fat substitute that will..

A

perform well in all food products

16
Q

How to reduce fats in foods

A
  • Modify animals diet to produce leaner meats
  • Introduce new species of animals that accumulate less fat in their body
  • Milk : remove fat (use 1%,2% skim)
  • Eggs remove fats (egg beaters-no yolk)
  • Meat: remove fat
  • Oilseeds: changed made through breeding and genetics to reduce level of saturated fats
17
Q

Mouthfeel of fat

A
  • Fat is a lubricant in the mouth
  • It helps clear food particles from teeth, tongue and gums during chewing
  • The creamy texture and smoothness sensation contribute to mouthfeel sensations.
18
Q

Fat plasticity

A
  • Physical property of a fat that describes its softness at a given temperature.
  • A plastic fat will respond to an external force by deforming when squeezed or spread, but holds its shape on a flat surface.
19
Q

Carbohydrate-based replacers includes..

A

Includes derivatives of cellulose, maltodextrins, gums, modified starches and polydextrose.

20
Q

Carbohydrate based replacers function as..

A

thickeners and stabilizers and when used to replace fat they add form and structure and act as emulsifiers when small amount of fat is present in the food.

21
Q

Carbohydrate based replacers produce ..

A

a mouthfeel that is similar to that associated with fat but they do not taste like fat and do not function like fat in cooking. (ex: Oatrim (made from hydrolyzed oat flour)

22
Q

Protein based replacements

A
  • ‘Simplesse’ is a microparticulated protein, which is produced by reshaping milk and egg white protein into tiny round particles.
  • Used to manufacture low-fat frozen and refrigerated products, but can not be used for frying.
23
Q

Simplesse process

A

produces protein particles so small that they are perceived as fluid by mouth.

24
Q

Fat based replacements

A
  • long chain FA can be combined with sucrose to produce a compound known as sucrose polyester.
  • This product is neither digested nor absorbed from the gastrointestinal tract but has characteristics similar to triglycerides in food preparation
25
Q

One of such fat based replacement approved for use in USA is

A

known as OLESTRA and goes by the brand name of OLEAN.

26
Q

Olestra

A
  • not approved for Canada
  • Olestra has a core molecule of sucrose to which 8 fatty acids are chemically bonded.
    The digestive enzymes do not recognize this structure and olestra passes through the digestive system undigested.
  • most successful of the fat substitutes because it can be used in cooking or frying and it tastes like fat.
27
Q

Safety concerns of olestra

A
  1. Presence in the large intestine causes diarrhea, has and cramping in people
  2. Can prevent absorption of fat soluble vitamins
  3. May cause the loss of essential phytochemicals such as carotenes from the body