lipids
methyl group
-CH3
essential fatty acids are essential for
-forming vital body structures -in immune system function -in function -forming cell membranes
negative health consequences of saturated fats
-increase in plaque buildup in the arteries -increase in LDL cholesterol -increase in risk of heart disease & stroke
why are oils hydrogenated
-makes them more solid or film -longer shelf life (unsaturated fats go bad quickly) -once believed to be healthier than animal fats b/c they come from plant oils
benefits of essential fatty acids
-omega-3 fatty acids can lower blood triglycerides & slow growth of plaque on the arteries -disease risk of hypertension, heart disease, and diabetes
trouble with trans fats
-raise LDL cholesterol & lower hDL cholesterol -raise risk of disease even more than saturated fats
health benefits of coconut oil despite its high saturated fat content
-raises HDL cholesterol -medium length chain triglycerides do not get turned into body fat -good for brain health -helps burn body fat
why does hydrogenation result in a mixture of saturated & trans fat
-turns double bonds to singles -switches some hydrogen atoms to the other side of the molecule
triglycerides are composed of what
3 fatty acids & a glycerol backbone
medium chain
6-10 carbon atoms
carboxyl group
COOH
unsaturated fatty acid shape
a bend or "kink" in the shape - more double bonds = more bends
emulsion
a mixture of two liquid phases that don't normally mix
functions of fat in food
adds flavor in food, creates a rich, creamy mouthfeel, shorten baked goods, & aeration
phospholipids as emulsifiers
because they have hydrophobic & hydrophilic portions, phospholipids can coat the oil to suspend it in water
does shortening or butter melt faster?
butter
does shortening or butter make a chewier cookie?
butter - contains 20% of water which helps gluten formation
examples of sterols
cholesterol and vitamin d
phospholipids
compounds consisting of a glycerol backbone with two fatty acids and one phosphate-containing group
examples of polyunsaturated fats
corn oil, safflower oil, soybean oil, sunflower oil, and fish oils
low smoke point oils
dips and dressings
sesame oil
distinct nutty flavor
lipases
fat-specific enzymes that assist in the breaking down of triglycerides
what part of the phospholipid is hydrophobic?
fatty acid "tail" - face towards oil
omega-3
fatty acids that have the first double bond on the 3rd carbon from the omega end
omega-6
first double bond on the 6th carbon from the omega end
omega-9
first double bond on the 9th carbon from the omega end
sources of omega-3 fatty acids
fish, fish oil capsules, walnuts, flax seeds, or chia seeds
smoke point - chemical composition will change altering what
flavor
what part of the phospholipid is hydrophilic
glycerol & phosphate "head" - face towards water
medium smoke point oils
good for baking or stir-frying
saturated fatty acids
have all single bonds between carbon atoms
unsaturated fatty acids
have at least one double bond between carbon atoms
polyunsaturated fatty acids
have multiple double bonds
monounsaturated fatty acids
have one double bond
trans- configuration
hydrogen atoms are on opposite sides of the double bond (straight-chain shape similar to saturated fats)
cis- configuration
hydrogen atoms are on the same side the double bond (bent shape)
how are triglycerides broken down
hydrolysis
why are unsaturated fats liquids (oil) at roomp temp
kinked structure does not allow molecules to pack together tightly
triglycerides can vary in
length, saturation, and location of double bonds
short chain
less than 6 carbons
phospholipid function
make up cell membranes, act as emulsifiers to keep fats suspended in solution
long chain
more than 12 carbons
where do saturated fats come from
most come from animal sources (lard, butter, beef tallow) & some come from plant sources (palm oil, coconut oil)
canola, safflower, corn oil
neutral flavor
what do USDA dietary guidelines recommend for saturated fats
no more than 10% of calories (200 per day) should come from saturated fats
hydrophobic
not soluble in water
olive oil
olive flavor good for salad dressings or dips
examples of monounsaturated fats
olive oil, canola oil, avocado
essential fatty acids
omega-3 & omega-6
lipids
organic compounds composers of carbon, hydrogen, and oxygen that are insoluble in water
why are omega-3 & omega-6 fatty acids essential
our body doesn't manufacture them so they are supplied from our diet
lecithin
phospholipid found in eggs
where can omega-6 essential fatty acids be found
plant oils
fats are used in frying to
prevent sticking to the pan, transfer heart, produce characteristic flavor of the fat when heated
hydrophilic
soluble in water
sources of omega-6 fatty acids
soybean oil & other vegetable oils, nuts, eggs, chicken
saturated fatty acid shape
straight-chain
mono & diglycerides
synthetically made phospholipids
are trans fatty acids unsaturated or saturated?
technically unsaturated but have the properties of a saturated fat
why are saturated fats solids at room temp
the straight-chain fatty acids pack together to make a solid
smoke points
the temperature at which an oil starts to smoke and break down into free fatty acids
shortening
to create a crumbly, flakey texture
aeration
traps air to add to fluffy texture
types of lipids
triglycerides (fat/oil), phospholipids, sterols
unsaturated fats
triglycerides high in fatty acids with at least one double bond
saturated fats
triglycerides high in saturated fatty acids
coconut oil
tropical flavor
considerations of fat food for cooking
usage: frying vs fresh, cooking duration & temp, taste & flavor
high smoke point oils
used for searing, browning, or deep frying
cholesterol
used to make hormones and vitamin d
examples of hydrogenated oils
vegetable shortening (crisco) & margarine
sterols
waxy compounds that are insoluble in water & have structures with carbon rings
hydrogenation
when hydrogen is added to an unsaturated fat at high pressure
