Ch 5: Lipids Flashcards
(55 cards)
chem structure of fatty acids
organic acid
C chains w H attached
- carboxylic acid group
- methyl group
fatty acid chain length
even # of C 18-C is most abundant found in food Long 12-24 C Medium 6-10 C Short less than 6 C
degree of unsaturation of fatty acids
amt of double bonds present
unsaturated fatty acids
monounsaturated- 1 double bond (point of unsaturation)
polyunsaturated- 2+ double bonds
saturated fatty acids
no double bonds b/w carbons
naming polyunsaturated fatty acids
- from first unit of unsaturation from methyl end
- omega number for monounsaturated FAs
triglycerides chemical structure
glycerol backbone w 3 fatty acids
- very few fatty acids are free in the body, most are part of triglycerides
how are triglycerides formed?
condensation reactions
- produce water from H and hydroxyl (OH-)
factors contributing to functional properties of triglycerides
chain length
degree of saturation
position of double bonds
properties of saturated triglycerides ex
the more saturated TG, the more solid at room temp it is
ex. animal fat
coconut and palm oil structures
firmer than most veg oils but still softer than animals fats
- bc of shorter chain length
8-14C
palm oil almost 50/50 saturated to polyunsaturated
shorter chain length = ?
softer at room temp
saturation of triglycerides provides __?
stability
unsaturated fatty acids oxidize more easily, causes spoiling
– manufactures place their products in air tight containers, add antioxidants, or hydrogenate their products to prevent spoiling
hydrogenation
H atoms added to unsaturated fatty acids
- makes liquid fat more solid at room temp.
- increases the shelf life of food
Trans - fatty acids
from partially hydrogenated, rather than completely hydrogenated fatty acids
- behave like saturated fats in the body
- cis bonds are not as negative healthwise as trans fatty acids
Phospholipids
plus ex.
act as emulsifier
- fatty acid portion makes fat soluble
- phosphate portion makes water soluble
ex. our cell membranes, allows water & fat soluble vit & hormones to pass through
ex 2. lipoproteins in our blood, transport fats through bloodstream
emulsifier
- a substance w both water-soluble and fat-soluble portions
- promotes the mixing of oils and fats in watery solutions
Lecithin
supplementation is problematic bc our liver makes all the lecithin that we need, therefore it is not an essential nutrient
micelle
emulsified fat
sterols
have multi ring structure
ex. cholesterol
cholesterol
- from animal prod. only
- made by liver, 800-1500mg/day
- used to make bile acids, sex and adrenal hormones, vitD
- procides structural support for our cell membranes
plant sterols
shown to decrease cholesterol levels and inhibit cholesterol absorption
- thus has been added to food such as margarine in an effort to decrease blood cholesterol
emulsification of fat
occurs in sm intestine
bile emulsifies fat, breaks down into fat droplets (micelles) that repel one another
enterophatic circulation
bile in GI tract has 2 possible fates:
- reabsorbed by sm intestine and sent back to liver to be recycled
- excreted (absorbed by soluble fibres) , may lower cholesterol levels