Lipids: Properties and Classes 21 Flashcards
What is one common characteristic with all lipids??
All are not water soluble. (Therefore fat acts as a barrier)
What are some major biological functions of lipids in the body?
- Barrier
- Hormones
- Immune function- Precursor to eicosanoids
- Insulation
- Energy storage and source (9kcal/g)
- Major component of cell membranes
Non-esterified FA or FFA
Head: carboxylic acid, Tail CH chain
- 99% in plasma bound to albumin or else toxic
- Fat break down occurs mostly in the liver and adipose tissue.
- Insulin inhibits FFA release
- Increase FFA during starvation. (Breaking down fats)
What are the major Classifications?
SCFA: 14
The degree of saturation is also important…
Saturated: no double bonds, Monounsaturated: one double bond.
Polyunsaturaed: More than 1 double bond.
What is the most common FA found?
Mostly 16Chain, even carbon (Add by 2C during synthesis). Most common is 14-18C.
Notation: Omega 18: 2 w6
Count from CH3 end.
Miller notation 18: 2 n-6
Subtract n from total C to get how many away from the COOH end.
What is the most common way to find FA?
Most are in cis formation. However if in trans they are usually monounsaturated FA. With few polyunsaturated trans FA. Trans is due to biohydrogenation of ruminant animals.
Saturated FA nomenclature: Do from C12-C18
C12: Lauric acid, coconut oil, palm oil
C14:Myristic acid, coconut oil, palm oil
C16:Palmitic acid, palm oil
C18:Stearic acid , most animal fats
Unsaturated FA nomenclature: C16-C22
C16:1w7 Palmitoleic acid SOURCE: seafood, beef C18:1w9 Oleic acid SOURCE: olive oil canola oil C18:2w6 Linoleic acid SOURCE: sunflower, safflower oils C18:3w3 Linolenic acid SOURCE: soybean and canola oil, flaxseeds C20:4w6 Arachiodonic acid SOURCE: eggs, most animal fats C20:5w3 Eicosapentaenoic acid (EPA) Seafood C22:6w3 Docosahexoenoic acid (DHA) Seafood
What are the benefits of omega 3 linolenic acid ?
Reduces the risk of heart disase and stroke. Helps prevent blood clots, lowers blood pressure. Great sources of linolenic acid are oils such as flaxseed and canola oil, nuts and seed such as walnuts, flaxseeds. vegetables such as soybeans.
EPA and DHA seafood: oysters.
What are some sources of omega 6?
Vegetable oils, safflower, sunflower oils. Arachodonic acid: sources are eggs and meat and poultry
What do you want the omega 6: omega 3 ratio to be?
Ideal is there’s more omega 6 than omega 3. 5:1 kind of deal. They compete for the same enzymes and their actions often oppose each other. Increasing omega-3 in the diet is best! Not reducing omega 6 b/c it’s still needed in the diet.
Recommendation of linolenic acid?
female: AI is 1.1g/day and male is 1.6g/day
Recommendation of linoleic aicd?
Female: AI 15g/day, men 17g/day
Glycerolid?
Glycerol backbown attached by ester linage to a FA. Alcohol + acid
C-OH HOOC^^^^^^^^^^^
COC=O^^^^^^^^^
Simple TG
All the same FA on the glycerol
Complex TG
Different FA on the glycerol (more common)
What are in position sn-1 and sn-3?
Saturated FA..therefore sn-2 is usually unsaturated FA.
What makes a fat short and liquid at room temperature? (Increase fluidity)
decrease chain length and increase double bonds.
Coconut oil
What causes a fat to decrease stability and be readily oxidized?
short chain length and more double bonds
Sources of SFA
coconut oil, butter, beef tallow, bacon,
Sources of MUFA
olive oil, coconut oil, peanut oil
Sources of PUFA
safflower oil, sunflower oil, soybean oil, canola oil for omega-3.
Hydrogenation of TG..what happens
Add on H’s to decrease the unsaturated FA
Changes MP, mouth feel and flow.
Bio product of hydrogenation?
Trans= bad. partial hydrogenation. Trans often increases LDL and decreases HDL.
Sources of trans fat
fast food, fried foods, shortening chips
Glycerophospholipids..why are they important?
Phospholipid bilayer.
They have hydrophilic head and hydrophobic tails.
Control passage in and out of compounds/ cells
What is the structure of a glycerophospholipid?
glycerol back bone with sn-1 and sn2 FA and phosphate group in sn-3.
sn-1 saturated and sn-2 unsaturated
What is the major phospholipid used in food industry?
Phosphohatidyl cholrine as a emulsifier (lecithin)
Glycosphingolipids structure?
amino alcohol and FA + sugar
What is the function of a glycosphinolipid?
Cell surface antigens, receptors. Lots in mylein sheath.
Cholesterol. What is the main form in the body?
Cholesterol ester- cholesterol + FA (main form)
or free cholesterol
What is the importance of cholesterol in the body?
It modulates membrane compressiblitity, permeability, fusibility, thickness and organization.
What are plant sterols called?
beta-sitosterol
What is the relationship between cholesterol and bile?
Bile acids are formed from cholesterol.
Once cholesterol are conjugated with taurine or glycine in the liver they are secreted in the bile.
Aid in digestion and absorption of fat and fat soluble vitamins in the intestine.
