Chapters 11 And 12 Flashcards
Describe unsaturated FA
Has double bonds in carbon chain which creates kink in FA
Two type of unsaturated FA
Polyunsaturated
Monounsaturated
Monounsaturated vs polyunsaturated
Monounsaturated contain only 1 double bond
Most abundant saturated FA
Palmitic
Most abundant monounsaturated FA
Oleic
Most abundant polunsaturated FA
Linoleic and alpha linoleic
What determines the melting point?
3 factors
- Chain length
- Degree of unsaturation
- Configuration of double bond
How does chain length affect melting point
short-chained FA’s have lower melting points
Degree of unsaturation effect on melting point
unsaturated FA’s have lower melting points
Configuration of double bond effect on melting point
cis form has lower melting point than trans
What is rancidity
The chemical deterioration of a fat caused by the uptake of oxygen (oxidation) or water (hydrolysis).
Explain hydrolytic rancidity
•Fatty acids break off from glycerol by lipase
2 effects of hydrolytic rancidity
- Release volatile fatty acids
* Off flavors
What is acrolein
By product of hydrolytic rancidity during deep frying
Explain oxidative rancidity
- Heat, light, free radicals break down fatty acids ( most start with singlet oxygen)
- Creates chain reaction
5 functional roles of fat in foods
Provide color
•Contribute to flavor
•Influence texture
- Cooking medium
- Emulsification
2 subgroups of texture that fat contributes to
- Tenderness
* Flakiness
3 main differences of margarine vs butter
Margarine is mostly oils where butter is mostly butter fat
Margarine has no cholesterol
Margarine has trans fat
What does hydrogenation do
Break double bonds and form saturated fat
3 effects of hydrogenation
●prevents rancidity
●raises melting point
●lose health benefits of unsaturated fats
•Winterizing-
process of chilling an oil to precipitate, filter, and remove any fat crystals
•Refining-
after extraction, refining removes undesirable gums, proteins, ketones
Cold Pressing-
mechanical pressing of seeds or olives at ambient temperatures
•Rendering-
first step in production of lard (from pigs) or tallow (from beef cattle and sheep) is extraction of fat from tissues; steamed to liquify
Interestification
Uses chemicals or enzymes to split fatty acids from glycerol, then reorganizes them on glycerol to form different triglycerides with less tendency to form coarse crystals.
Usually blend hard fats (palm oil, fully hydrogenated oil) with liquid oils to produce fats with intermediate characteristics.
Tempering?
Look in book
Types of oils and their composition?
K
Describe a saturated FA
Chain contains no double bonds
