Lipids Flashcards
Cis fatty acids
Two hydrogen atoms are on the same side of the double bond
Trans fatty acids
Two hydrogen atoms on opposite sides of the double bond
Essential fatty acids
Must be obtained from food
Cannot be manufactured by body
Linoleic acid, linolenic acid
Examples of saturated fatty acids
Stearic acid
Butyric acid
Monounsaturated
Oleic acid
Polyunsaturated fatty acids
Linoleic acid
Linolenic acid
Arachidonic acid
Properties
Solubility Absorption of flavour Effect of heat Rancidity Hydrogenation Plasticity Emulsions
Solubility
Insoluble in water
Soluble in organic solvents
Melting Point
fats between 30-40,
oils just below room temperature
Rancidity
Oxidative: Oxygen reacts with carbon in double bond in unsaturated chain. Antioxidants prevent
Hydrolytic: Reaction of enzymes or microorganisms
Hydrogenation
Hydrogen added to unsaturated fatty acid with nickel as catalyst. Converts into saturated fat. Double bonds broken and hydrogen attaches itself to carbon
Plasticity
Lipids can have properties of both a solid and a liquid
Emulsifier
Lowers surface tension between oil and water
Hydrophilic tail attaches to water
Hydrophobic tail attaches to oil
Stabilises the mixture and prevents separation
Biological functions
Heat and energy Provide insulation Protects delicate organs Vitamins A, D, E, K Omega-3 aids brain function and lowers cholesterol
Digestion by liver
Bile
Bile salts
Fat molecules
Emulsified fat molecules
Digestion by pancreas
Pancreatic juice
Lipase
Lipids
Glycerol and fatty acid
Digestion by small intestine
Intestinal juice
Intestinal lipase
Lipids
Fatty acid and glycerol
Smoke Point
Lipids begin to decompose into glycerol and 3 fatty acids
Blue haze emerges
Acrid-smelling compound called acrolein is present
Fats: 200
Oils: 250
Flash point
Lipids spontaneously burst into flames
Fats: 310
Oils: 325
