Topic 5: Part C

Question 1

Winterization of fats

Answer 1

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

Question 2

Oils can become cloudy at lower temps because ..

Answer 2

some of the triglyceride molecules crystallize and become solid

Question 3

Winterization of fats involved lowering the ..

Answer 3

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

Question 4

The oil is filtered to remove the crystals the ..

Answer 4

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

Question 5

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

Answer 5

rancidity

Question 6

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

Answer 6

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

Question 7

2 types of rancidity

Answer 7

• oxidative rancidity

- hydrolytic rancidity

Question 8

Oxidative rancidity

Answer 8

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

Question 9

Oxidative reaction begins with the ..

Answer 9

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

Question 10

During oxidative reactions, Hydroperoxide molecules readily breakdown into..

Answer 10

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

Question 11

Oxidative damage can be ..

Answer 11

prevented or slowed down through use of antioxidants

Question 12

Hydrolytic rancidity

Answer 12

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.


Question 13

Importance of fats/oils in foods

Answer 13

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.

Question 14

Fat replacers

Answer 14

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

Question 15

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

Answer 15

perform well in all food products

Question 16

How to reduce fats in foods

Answer 16

• 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

Question 17

Mouthfeel of fat

Answer 17

• 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.

Question 18

Fat plasticity

Answer 18

• 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.

Question 19

Carbohydrate-based replacers includes..

Answer 19

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

Question 20

Carbohydrate based replacers function as..

Answer 20

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.

Question 21

Carbohydrate based replacers produce ..

Answer 21

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)

Question 22

Protein based replacements

Answer 22

• ‘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.

Question 23

Simplesse process

Answer 23

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

Question 24

Fat based replacements

Answer 24

• 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

Question 25

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

Answer 25

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

Question 26

Olestra

Answer 26

- 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.

Question 27

Safety concerns of olestra

Answer 27

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