Lipids Flashcards
What’s a triglyceride made of
Three fatty acids
One glycerol
3ways to classify lipids
Degree of saturation
Source (oil/fat)
Essential or non essential fatty acids
Three types of fatty acids
Saturated fatty acids
Mono unsaturated fatty acids
Poly unsaturated fatty acids
How does a lipid become saturated
Hydrogen
Difference between cis and trans fatty acids
Cis has hydrogen on the same side of the double bonds. Unsaturated fatty acids food
Trans fatty acids have hydrogen on either side of the double bond, developed during processing, bad for yolk
What are essential fatty acids
Cannot be made in the body so must be obtained from food
Function of EFAs
Cell membranes
Reduce cholesterol
Examples of EFAs
Linoleic fish oil
Linolenic corn oil
Examples of polyunsaturated fatty acids
Arachidonic acid
Sources of omega 3 fatty acid
Oily fish
Fish oil
Nuts seed
Fortified eggs
Functions of omega 3 fatty acids
Reduce the risk of CHD, heard attacks and strokes by raising hDL and reducing LDL
Prevent blood clots
Aids foetal brain development and brain functioning
Properties of lipids
Solubility Effect by heat Plasticity Rancidity Hydrogenation Emulsions Stability
Melting temp
30-40
Boiling point
175-195
Smoke point
When lipids are overheated they decompose. It produces a blue haze or smoke and give off an acrid smell
Flash point
Extreme overheating causes the vapour to spontaneously ignite
How does a fat become more solid
Add hydrogen
More saturated
Two types of rancidity
Oxidative (oxygen)
Hydrolytic (enzymes or bacteria break down)
Temporary emulsion
Shaking eg vinegariette
Permanent emulsion
Using an emulsifier. Eg lecithin in egg for mayonnaise
What is a colloidal solution
A solution with suspended microscopic insoluble particles distributed evenly through another substance
Biological functions of lipids
Heat and energy Insulated body (adipose tissue) Protects important organs Fat soluble vitamins ADEk Provide omega 3 fatty acids Essential fatty acids
Enzyme that breaks down fat
Lipase
What does lipase break lipids knot
Fatty acids and glycerol
Organs involved in digestion of lipid
Pancreas -pancreatic juice
Liver -bile
Small intestine -intestinal juice
Example of a saturated fatty acid
What’s its plasticity at room temperature
Butyric acid
Solid at room temp
Example of a monounsaturated fatty acid
What’s its plasticity at room temperature
Oleic acid in corn
Liquid at room temperature
Example of polyunsaturated fatty acid.
What’s its plasticity at room temp
Linoleic acid in nuts and seeds
Soft as room temperature
How does oxidative rancidity occur
Oxygen joins with carbon atom in double bond
Releases unpleasant smell
How does hydrolytic rancidity occur
Enzymes break fat down into fatty acids and glycerol
Gives unpleasant taste and smell
