4

Question 1

Mono and diglycerides

Answer 1

Mono and diglycerides are partially soluble and used as emulsifiers because the polar end of the glycerol backbone is available for water or water soluble molecule

Question 2

Omega is from the

Answer 2

Methyl end of TGs

Question 3

Cis and trans

Answer 3

Geometric isomers

Question 4

Fatty acid composition in a fat or oil

Answer 4

Hydrolyzing all the ester bonds with a strong base (to liberate the FA from the glycerol).
FFA (free fatty acid) content is the presence of FA molecules in a fat or oil, is usually low (<1%) except olive oil.

Question 5

Saturation of oils

Answer 5

Tropical oils (palm, coconut) are exceptions because they have more saturated than unsaturated but still have low melting point because of short chain lengths.Lipids from fish soures tend to be highly polyunsaturated oils (ome3)

Question 6

Hydrogenation

Answer 6

Catalytic hydrogenation for longer shelf life, greater stability and lower cost than lard, faster dissolving and setting in chocolate products. Decreasing number of unsaturation by adding H2 (can cause cis to trans). Widely used in margarines and shortenings. Because of risks to CVD, interesterification is now used.

Question 7

Nutritional importance of fats/lipids

Answer 7

Source of energy, source of EFAs, Carriers of Vit A, D, E, K. Help regulate body temperature (brown), protection of vital organs from injury, cell production (cell membranes), produces hormones (vit D, sterols,etc).

Question 8

Functional properties of lipids/fats in food

Answer 8

Heat transfer agent (because of high smoking point sometimes >200C). High T and loss of water promote Maillard reaction. Oil is absorbed by food (caloric content and taste).
Lipids tenderize baked products by shortening flour’s protein strands which are chewy and tough. Fat to flour ratio determines flakiness. Lipids with high melting points work best for biscuits, pies, puff pastry whereas oils can be used for quick mix batters.
Lubricating agents (emulsions) : bread (butter which is w in oil) and salad (salad dressing is o in water).
Aeration:lipid and air are hydrophobic so easy to incorporate air and contribute to volume and height of product
Enhancing flavors by dissoling and dispersing flavor compounds and and butter,margarine have flavor on their own
Contribute to texture, mouthfeel and satiety

Question 9

Component that influences functional properties of fat

Answer 9

Plasticity of fat. All lipids have more than one triglyceride. That’s why there is a termperature range.
Wiithin this temperature range: it’s called with mixture of solid fat and liquid oil, defined by Solid Fat Content (SFC). The plasticity (ability to be molded and spread) depends on SFC.

Question 10

Fat substitutes

Answer 10

Olestra, sugar polyester, not used anymore because of side effects (diarrhea). MCC. Both are not metabolized by the body = no caloric

Question 11

Deterioration of fat

Answer 11

Autoxidation (oxidative rancidity) because of O2 causes off flavors because of randicity. Faster for unsaturated. Antioxydants (Vit E) can be added to delay oxidation by being oxidized à leur place.
Lipolysis is another deteriorative reaction: hydrolysis of triglycerides producing free Fas. Occurs at high T in presence of water(from food that leaks) = FRYING.
Because free Fas have lower mp than triglycerides, lipolysis results in a reduction in smoke point (discard oil). Flash point is T at which it flames.