Final exam Flashcards
(105 cards)
Functions of dietary Fats
1.Supply a concentrated source of energy 9kcal/g.
2.Supply fat-soluble nutrients: Eseential fatty acids (linoleic acid & a-linolenic acid), vitamins A,D,E AND K
3.Increase the flavour and palatability of foods
4.contribute to satiety (keeps you fuller)
5.provides building blocks of cell membrane (fat gives cell membrane flexibility)
6.body fat provides protections
what are lipids and name three
a family of organic compounds soluble in organic solvents but not in water, triglycerides, phospholipids and sterols
What does saturation/unsaturation in fat do
the degree of unsaturation influences firmness of fats at room temp, saturated fats are solid like butter while unsaturated fats are usually liquid like oil
Triglycerides
consists of three fatty acids attached to a three carbon glycerol backbone
Saturated fatty acids
saturated with maximum hydrogen meaning they have no carbons bonded together with a double bond. Stacks well and solid at room temp,
Unsaturated fatty acids/two types and forms
less hydrogen are unsaturated has double bonds, liquid at room temp, come from plant based foods. (one double bond)Monounsaturated/polyunsaturated(trans/cis)
Essential Fatty acids/benefits
Polyunsaturated(omege 3-6 fatty acids)
raw materials for eicosanoids (act like hormones)
Affect:
Muscle contraction/relaxation
blood vessel dilation/constriction
blood clot formation
blood lipid regulation
immune response (includes inflammation)
Omega 6 fatty acid
Omega-6–linoleic acid–arachidonic acid
Linoleic acid is an essential fatty acid from the omega 6 family
Linoleic acid is required for:
Growth, maintenance of healthy skin, normal functioning of the reproductive system
Physiological importance of linoleic acid derivatives:
found in cell membrane
high amounts in nerves and the brain
components involved in regulating blood pressure and blood clotting
Food sources of omega 6
sunflower, corn, and soybean oils
Omega 3 fatty acids
Omega-3–a-Linolenic acid==DHA and EPA
ALA is an essential fatty acid from the omega 3 family
a-linolenic acid, eicosapentanoic acid and docosahe are the primary members of the omega 3 family.
Physiological importance of a-linolenic acid
required as a structural component of cell membranes, found in high concentrations in the brain and eyes, a precursor for compounds that regulate blood pressure and clotting.
Omega 3 food sources
walnuts, flaxseed, canola oil and soyabeans
Fat in fish
DHA and EPA have 4-6 double bond which gives them a very high degree of unsaturation making these fluid at cold temprature (flexible), The fat on fish is unsaturated,
Benefits of fat in fish
reduces risk of heart attack, plaqure formation on artries, high blood pressure, risk of stroke and provides protection against irregular heart beat and sudden death.
Hydrogenation
A process by which hydrogen is added to liquid unsaturated fats making them more saturated and solid. Shelf life, cooking properties and taste are improved.
Two drawbacks of hydrogenation
- Hydrogenated vegetable oils have more saturated fat
- changes the structure of the unsaturated fatty acids converts some fats into trans fats
Cis-fatty acid
Hydrogen is on the same side of the chain does not pack well more liquid
Trans fat
more linear the hydrogen is on opposite sides of chain, packs easily behaves like saturated fat
risk of trans fatty acid
raises LDL blood cholesterol levels more than dietary cholesterol, saturated fats or any other type of fat, no safe level of trans fat,
sterols
large complicated ring carbon molecules, cholesterol found only in animal products, tasteless, odorless, clear liquid in lean and fat animal product
Cholestrol facts and functions
found in every cell in your body (cell membranes, serves as the building block for estrogen, vitamin D and testosterone, A major component of nerves and the brain, cannot be used for energy