Lipids Part 1 Flashcards
(27 cards)
Biological significance of fats
Act as fuel in the body Caloric value 9kcals/gm
Fats underneath skin exerts insulating effects
Padding and protecting internal organs
Building materials. Cholesterol-hormone synthesis
Lipids
Consists of fixed oils,fats,waxes
Esters of long chains fatty acids and alcohols or of closely related derivatives
Examples of fixed oils fats and waxes
Fixed oils -peanut oil, castor oil
Fats- animals lard
Waxes- beeswax
Primary function of lipids
Energy storage/source of energy
Boiling point of fixed oils and Fats
Lower bp fixed oil
Higher bp fat
Physical properties of cocoa butter
Solid from plant
Physical properties of cod liver oil
Liquid from fish
Physical properties of fixed oil and saturated fats
Fixed oil roomtemp liquid from plant
Saturated solid
Saturated fatty acids
Butyric
Caproic
Caprylic
Capric
PUFA
polyunsaturated fatty acid
Two or more double bonds
Members of omega 3 and omega 6 fa essential fatty acids
Essential fatty acids
Linolenic acid omega 3 FA
Linoleic acid omega 6 FA
Richest source of PUFA
Vegetable oils
Corn sunflower cotton seed oils
EFA- omega 3 and 6 FAs
Omega indicates first double bond from the methyl group
First point of unsaturated if next to the third carbon (omega 3 fa)
Great significance on human nutrition and health issues
Importance of lipids
Energy storage
Signaling molecule
Structural component of cell membrane
Properties of lipids
Physical- fixed oil
Greasy
Lighter than water
Insoluble in water
Soluble in organic solvents
Properties of lipids
Chemical
Hydrolysis-addition of water trigly yield glycerol and fatty acid
Rancidity- intial products aldehydes and ketones
Final products oxidation: acid RCOOH
Acrolein test- prescence of glycerol/ formation of propenal
Enzyme in hydrolysis
Lipase (catalyze)
Rancidity
Sesame walnut factor
Exposure light/air
Oxidation
Unpleasant odor/flavor
Byproduct of lipids smelly breath
Acrolein test
Dehydrating agent fat
Potassium bisulfate KHSO4
To form unsaturated aldehyde
Pungent irritating odor
Has triglycerol
Acid value or acid number
The number of mg of KOH required to neutralize the free fatty acids in 1g of substance
Saponification value
Number of miligarams of KOH to neutralize the free fatty acids and saponify the esters contained in 1 g of the substance.
Iodine number
Number of grams of iodine absorbed under prescribed conditions by 100 grams of substance indicates the degree of unsat
Methods of obtaining fixed oils of vegetables and animal origin
Fixed oil fats of vegetable origin are obtained by expression in hydraulic presses
Virgin oil or a cold pressed oil if the expression is carried out in cold
Hot expression if the expression is carried out in heat
2. Sometimes organic solvents are used for extraction oils
What are the classes of lipids based on its ability to absorb oxygen from air
Drying oils
Semidrying oils
Nondrying oils
