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TRIGLYCERIDES
BY
ABHISHEK JAGUESSAR
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The Lipids: Triglycerides,Phospholipids and Sterols
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Lipids Objectives
1. Understand the chemical composition and differencesbetween fats
2. Explain the structural and functional processes of
triglycerides, phospholipids, and sterols 3. Describe the process of fat digestion and absorption
4. Discuss the different types of lipoproteins in the body
5. Clarify the recommended intakes of fat and essential fatty
acid requirements to meet daily nutritive needs 6. Describe the health-risk factors with over consumption of
lipids in the diet
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Fatty Acids
The Length of the Carbon Chain long-chain, medium-chain, short-chain
The Degree of Unsaturation saturated, unsaturated, monounsaturated,
polyunsaturated
The Location of Double Bonds omega-3 fatty acid, omega-6 fatty acid
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The Length of the Carbon Chain
Short-chain Fatty Acid
(less than 6 carbons)
Medium-chain Fatty Acid
(6-10 carbons)
Long-chain Fatty Acid
(12 or more carbons)
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Fatty Acids are Key Building Blocks
Saturated Fatty Acid
All single bonds between carbons
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Monounsaturated Fatty Acid
(MUFA)
One carbon-carbon double bond
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Polyunsaturated Fatty Acid
(PUFA)
More than one carbon-carbon double bond
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Location of Double Bonds
PUFA are identified by position of the
double bond nearest the methyl end (CH3)
of the carbon chain; this is described as a
omega number;
If PUFA has first double bond 3 carbons
away from the methyl end=omega 3 FA
6 carbons from methyl end=omega 6 FA
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Degree of Unsaturation
Firmness saturated vs. unsaturated
Stability oxidation, antioxidants
Hydrogenation advantages, disadvantages
Trans-Fatty Acids from hydrogenation
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HydrogenationHydrogenation
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Cis-fatty acid: Hs on same side of the double bond; fold intoa U-like formation; naturally occurring;
Trans-fatty acid: Hs on opposite side of double bond; more
linear; occur in partially hydrogenated foods;
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1. Shortening
2. Cube margarine:vegetable oil blend (partially
hydrogenated soybean oil and liquid
soybean oil), water, whey, etc
1 Tbsp: 9 g fat; 2 g SFA; 2 g PUFA;
2.5 g MUFA;
3. Light Tub Margarine:water, liquid and partially hydro-
genated soybean oil, maltodextrin,etc.
1 Tbsp: 6 g fat; 1 g SFA;
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But, is all Trans FatBad?
CLA
Conjugated Linoleic Acid
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Essential Fatty Acids (EFA)
Omega-3:Eicosopentaenoic acid (EPA)
Docosahexaenoic acid (DHA)
Alpha-linolenic acid (ALA) flaxseed--most, canola (rapeseed), soybean, walnut,
wheat germ
body can make some EPA and DHA from ALA
Omega-6 corn, safflower, cottonseed, sesame, sunflower
Linoleic acid
FISH
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Omega-3
Omega-6
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Omega-3 Fatty Acids
Associated with: anti-inflammatory, antithrombotic, antiarrhythmic,
hypolipidemic, vasodilatory properties
Inflammatory conditions
Ulcerative colitis, Crohns
Cardiovascular disease
Type 2 diabetes * Mental functionRenal disease * Growth and
development
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Essential Fatty Acid Deficiency
Classical symptoms include: growth retardation, reproductive failure, skin
lesions, kidney and liver disorders, subtle
neurological and visual problems
People with chronic intestinal diseasesDepression--omega-3
?inadequate intake alters brain activity or
depression alters fatty acid metabolism?
Attention Deficit Hyperactivity Disorder lower levels of omega-3--more behavioral problems
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Eicosanoids: made from EFA--derivatives of 20-carbon fatty acids;
--affect cells where they are made;--have different effects in different cells
--cause muscles to contract and muscles to relax;
--help regulate blood pressure, blood clotformation, blood lipids, and immune response;
--participate in immune response to injury and
infection, producing fever, inflammation, and
pain;
--include:prostaglandins, thromboxanes,
leukotrienes
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Triglycerides
StructureGlycerol + 3 fatty acids
Functions Energy source
9 kcals per gramForm of stored energy in adipose
tissue
Insulation and protection
Carrier of fat-soluble vitamins
Sensory properties in food
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Triglycerides: lipids composed of three fatty acids
attached to a glycerol
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TriglyceridesFood sources
fats and oils
butter, margarine, meat, baked goods, snack foods,
salad dressings, dairy products, nuts, seeds
Sources of omega-3 fatty acids
Soybean, canola, walnut, flaxseed oils
Salmon, tuna, mackerel
Sources of omega-6 fatty acids
Vegetable oils
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Fatty Acids in Common Food FatsFatty Acids in Common Food Fats
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PhospholipidsStructure
Glycerol + 2 fatty acids + phosphate
group
FunctionsComponent of cell membranes
Lipid transport as part of lipoproteins
Emulsifiers
Phosphatidylcholine
Food sources Egg yolks, liver, soybeans, peanuts
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Cell membranes are phospholipid bilayers
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Sterols: Cholesterol
FunctionsComponent of cell membranes
Precursor to other substancesSterol hormones
Vitamin DBile acids
Synthesis
Made mainly in the liverFood sources
Found only in animal foods
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Lipid Digestion
In the Mouth hard fats begin to melt; lingual lipase
In the Stomach gastric lipase--SCFA
In the Small Intestine release of CCK; bile-emulsifier; fat drawn into
surrounding watery fluids; intestinal lipases;
remove each TG fatty acid; leave glycerol;Bile Routes
reabsorbed or trapped by dietary fiber
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Olestra
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OlestraSucrose + fatty acids
Indigestible provides zero kcals
Reduces absorption of fat-soluble
vitaminsSo many fatty acid chains are crowded
around the core, the digestive enzymes
cannot find a breaking point
Orlistat (Xenical)* binds to active site of GI lipase and blocks its
activity; thus, lipase cant break TG down to
component parts; TG remains undigested
and unabsorbed