Unit 2.2 Flashcards
What lipids are solid at room temperature?
Fats (triglycerides and saturated fatty acids)
What lipids are liquid at room temp?
Oils (unsaturated fatty acids)
What is the main form of lipids in foods and body? What are they used for?
Triglycerides
Energy storage
Energy in lipids
9 Kcal//g (energy dense)
What is the largest source of energy?
TAGs
What are precursors of ecosanoids?
Phospholipids
Functions of TAGs
Provide energy (FA)
Store energy (stable and dry)
transport of lipid-soluble nutrients
What are the most common lipids in biological membranes?
Phospholipids (phosphoglycerolipids)
Function of phospholipids
Digestion of dietary lipids (lecithin)
Sources of eicosanoids (at C-2)
Transport of lipid soluble nutrients
Cholesterol’s are sources of…..?
All steroid hormones
Bile salts for lipid digestion
Vitamin D
Function of cholesterol
Component of biological membranes
Transport of lipid soluble nutrients
General formula for simple lipids
R-COOH
Fatty acids can be…..
Short, medium and long-chain
Saturated (SFA)
Unsaturated (UFA)
- Monounsaturated (MUFA)
- Polyunsaturated (PUFA)
Trans (TFA, mostly man-made)
Nonessential (NEFA)
Essential (EFA
- Linoleate, linoleic acid (C18:2, omega 6)
- Linolenate, linolenic acid (C18:3, omega 3)
Carbon chain for..
Saturated FA
Monounsaturated FA
Polyunsaturated FA
C18:0
C18:1
C18:2
What fatty acids are more common in foods? Cis or trans?
Cis
Cells only make cis fatty acids
Where are trans fats primarily found?
Foods containing hydrogenated fats such as margarine, shortening and deep fat-fried foods
When are cis FA converted to trans FA?
Primarily during storage, process and cooking
Omega-3… first double bond is located where?
On the 3rd carbon from them omega end
Where is the double bond located on omega-6?
On the 6th carbon from the omega end
Name examples of SFA
Coconut oil
Butter
Palm oil
Lard or beef fat
Some sources from MFA
Olive oil
Canola oil
Peanut oil
Name some sources of PFA
Safflower oil
Sunflower oil
Corn oil
Soybean oil
Sources of TFA
Tub margarine
Stick Margarine
Shortening
Plant oils contain SFA from 50%-90% in ____ and ____ oils
Palm
Coconut
Why are emulsifiers typically added?
To improve texture
What are some common emulsifiers
Lecithins
Monoglycerides
Diglycerides
Polysorbate (60,80)
Egg whites
Egg yolks
Whole eggs (no shit, if egg whites and yolks are in here)
When fat is removed, what is typically added in its place?
Sugars
What is often used in soft serve ice cream
Fat replacements, such as gum fiber
What is rancidity? (I guess that’s how I should ask……)
Decomposed oils
Breakdown of the C=C bonds by UV light and/or O2
Problems with rancid food..
Unpleasant odor and flavor
PUFA more susceptible
Limited shelf life
Ways to prevent rancidity
Vacuum-pack
Hydrogenation *
Addition of natural antioxidants
Addition of artificial antioxidants
Natural antioxidants added to prevent rancidity
Vitamin E (tocopherols, tocotrienols)
Vitamin C (ascorbate)
What artificial antioxidants are added to prevent rancidity
Butylated hydroxyanisol (BHA)
Butylated hydroxytoluene (BHT)
How do trans fatty calcium form
By partial hydrogenation of unsaturated FA
Why are trans fatty acids added to foods
To increase shelf life or stability at high temps of oils used in cooking (especially deep frying)
What allows a given fatty acid to adopt an extended conformation
A trans double bond
Trans FA can pack more regularly and show higher _____ ____ than cis forms
Melting points
Consuming trans fats increases risk of:
Cardiovascular disease
—avoid deep-frying partially hydrogenated veggie oils
Lipid digestion in the stomach
Only minor digestion of fat through the action of lipase enzymes
Fat digestion and the liver
Liver produces bile, stored in the gallbladder and released through the bile duct into the small intestine. Bile aids in fat digestion and absorption by emulsifying lipids in the digestive juices
Lipid digestion and the pancrea
Pancreas secretes a mixture of enzymes, including lipase, into the small intestine
Lipid digestion in the small intestine
Primary site for digestion and absorption of lipids
Once absorbed, long-chain fatty acids are packaged for transport through the lymph and bloodstream (shorter-chain fatty acids are absorbed directly into portal circulation)
Lipid digestion in the large intestine
Less than 5% of ingested fat is normally excreted in the feces
Substrate kid pancreatic lipase (and colipase)
TAGs
Substrates for phospholipase A2
Phospholipids
Substrate of cholesterol ester hydrolase
Cholesterol esters
How much dietary fat is absorbed?
Where?
95%
Diffused into absorptive cells
Which fatty acids are water soluble?
Where do they enter
Short and medium-chain (<12C) fatty acids
The portal system
Which fatty acids are not water soluble?
What are they reformed into?
Where do they enter?
Long-chain fatty acids
Triglycerides
Lymphatic system
Key role of chylomicron
Carries dietary fat from the small intestine to cells
Key role of VLDL
Carries lipids made and taken up by the liver to cells
Key role of LDL
Carries cholesterol made by the liver and from other sources to cells
Key role of HDL
Contributes to cholesterol removal from cells and, in turn, excretion of it from the body
What binds to LDL?
How is it taken up?
Receptors on the cell surface (mostly liver cells)
Endocytosis
Receptor pathway for LDL process is enhanced by what?
Diets low in cholesterol and saturated fat
HDL is synthesized by:
It is a high proportion of:
Liver and intestine
Protein
Functions of HDL
Picks up cholesterol from dying cells and blood
Transfers cholesterol to other lipoproteins
Can transfer directly back to the liver (reverse cholesterol transport)
Blocks oxidation of LDL *
Can closely predict risk of CVD*
Functions of antioxidants
Reduce oxidation (LDL)
Slow down LDL update into scavenger cells
Antioxidants found in plant foods
Ascorbate
Vitamin E
Lycopene
Carotenoids
Resveratrol
Sulforaphane
Anthocyanins
What removes oxidized LDL from circulation?
Scavenger WBC
Purpose of the scavenger pathway
Prevents oxidized LDL from returning to circulation
Build-up of plaque on walls of the blood vessels leads to what?
Atherosclerosis
What enhances the process plaque buildup in atherosclerosis?
Diets high in cholesterol, saturated fat and trans fat
Omega-3, AKA
Alpha-linolenic acid
Omega-6, AKA:
Linoleic acid
Omega-3 and omega-6 are ______ fatty acids
Polyunsaturated
Omega 3 includes:
Docosahexaenoic acid (DHA)
Eicosapentaenoic acid (EPA)
Which omega includes arachidonic acid?
Omega-6
Which omega is pro-inflammatory ?
Omega-6
Alpha-linolenic acid is found in:
Fish
Canola oil
Soybean oil
Walnuts
Flax seeds
What is the original source of omega 3s?
Micoalgae
Omega-3 provides what health benefits?
Cardiovascular
Linoleic acid is found in:
Many foods, particularly plant oils
Excess intake of omega-6 may cause:
General inflammation and increase blood pressure
Can also increase blood clotting
Benefits of DHA and EPA
Decrease blood clotting
Reduce heart attack
Decrease inflammation
