week 5 lipids Flashcards
what are the good lipids
unsaturated
what are the bad lipids
saturated
the very bad lipids
trans
functions
-energy, 9kcal/g. takes less energy to store and holds less water than carbohydrates
-makes up the lipid bilayer in cell membrane
- protection ans insulation
-adds taste, texture and smell to food
-aids in satiety -convert to other molecules needed by the body
-carries and stores soluble vitamins
- myelin sheath is made out of fat
the fatty acid structure
the basic building block of a lipid is called a fatty acid
- made of carbon, hydrogen and oxygen
the chemistry of lipids
the structure resembles the letter E, with one glycerol and 3 fatty acid chains attached
- FAs can be 4-24 carbons long , 18 C are most common
- can be saturated or unsaturated
unsaturated fatty acids
- a carbon-carbon double bond is a point of unsaturation. Fatty acids that have a double bond are unsaturated fatty acids
- theses cab be monounsaturated or polyunsaturated
location of the =
- identified by the position of the double bond nearest the methyl end, which is described by an omega number
- first = 3 carbon away from the methyl end us an omega 3fatty acid
naming fatty acids
short chain < 6C
medium chain6-12C
Long Chain > 12C
degree of saturation
the degree of saturation influences the firmness of fats at room temp
- the shorter the chain, the softer the fat is at room temperature
-butter = saturated = solid at room temp
- olive oil = unsaturated = liquid at room temp
saturated (health)
solid at room temperature, can stick to artery walls
-found mostly in animal products
- generally less healthy
unsaturated (health)
liquid at room temp
found mostly in plant foods
generally more healthy
stability
saturation influences stability, all fats spoil when exposed to oxygen
- poly unsaturated fats spoil faster due to unstable double bonds
hydrogenation
point of unsaturation are saturation by adding H. protects against oxidation and makes liquids more solid, improving texture of foods
trans fats
most often a fat is partially hydrogenated and some double bonds that remain after processing change from cis to trans
- in nature most double bonds are cis configuration
what are transfats
- made by the process of hydrogenation
- in the body, behave like saturated fats = raise blood cholesterol
- a small amount of trans fats come from natural sources and at current levels of consumption, natural trans fats have little, if any effect on blood lipids
butter
all natural right from cow
tastes great, conjugated linoleic is naturally found, some evidence to help prevent cancer
saturated
MARGARINE
could be hydrogenated or not
- plant fat , unsaturated
doesn’t provide same effect in food products
triglycerides
FAs often occur as free FAs, most often they are incorporated into triglycerides
- lipids composed of 3 FAs attached to a glycerol molecule
-condensation reaction combines a H form from the glycerol and an OH form the fatty acid, forming H2O and a bond between the glycerol and FA
Phospholipids
Lecithin
The most common phospholipid
One glycerol, 2 FAs, one P group with a
molecule of choline
FAs make phospholipids soluble in fat,
while the P group allows them to dissolve
in water
Adds versatility in the food industry
Phospholipids act as emulsifiers to mix
fats with water
Mayo and chocolate bars
Phospholipids
phospholipids in food
Found naturally in eggs, liver, soybeans, wheat germ, peanuts. As
lecithin.
phospholipids role
Major parts of our cell membranes - help vitamins and hormones to
pass in/out of cells, & help keep fats suspended in blood & body fluids
phospholipids in the liver
The liver makes all the lecithin that a person needs. Lecithin
supplements are pointless because the intestine hydrolyzes most of it
before it passes into the tissues. Lecithin is NOT an essential nutrient.
sterol - compounds
multiple ring structure
cholesterol
