Lectures 6 _ 7 - Lipid Digestion _ Absorption B_W

Lectures 6 _ 7 - Lipid Digestion _ Absorption B_W - Lipids...

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1 Lipids 9/19 and 9/21/11 S.E. Fleming Recommended readings: 1 Lecture Outline Introduction Major lipids in our diet Phospholipids Sterols Digestion and absorption of dietary lipid Chylomicrons Lipoprotein particles LDL HDL Functions of lipid Lipids and disease prevention Summary 2 Lipids 3 Lipid is the chemical term for fat. Lipids contribute texture, taste, flavor and aroma to foods. Source of energy for our bodies Fats and oils contain 9 calories per gram. Aids in absorption of fat soluble vitamins (Vit A, D, E The typical American diet contains about 33% of its energy from fat. In the body, lipids are an important part of cell membranes Lipids are a main component of cell membranes 4 5 Fat Intake Affects Health Lecture Outline Introduction Major lipids in our diet Phospholipids Sterols Digestion and absorption of dietary lipid Chylomicrons Lipoprotein particles LDL HDL Functions of lipid Lipids and disease prevention Summary 6
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2 7 Triglycerides Triglycerides are the major form of lipid in food and in the body. Fatty Acids Long chains of carbon atoms with an acid group at the end. Forms: Saturated (no C=C) Monounsaturated (one C=C) Polyunsaturated (several C=C) Cis and trans types of unsaturated fatty acid 8 Fatty Acids 9 The carbon chains of fatty acids vary in length from a few to 20 or more carbons. Short chain fatty acids range from 4 7 carbons and remain liquid at room temperature. Saturated fatty acids contain carbons in a chain that are bound to two hydrogens. Unsaturated fatty acids contain some carbons that are not saturated with hydrogens. Omega 3 and omega 6 fatty acids are unsaturated fatty acids. Most animal fats contain saturated fatty acids. 10 Fatty Acids: Saturation 11 Omega 3 and Omega 6 Fatty Acids Why are we discussing the chemistry? Fatty acids are not all created equal. Each has a different function and effect on heart disease Their structures determine their function 12
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3 Chemistry of fatty acids influences their characteristics and health effects Fatty acid # Carbons # double bonds Consistency at room temp Food example Health effect Negative = No effect=0 Positive = + Acetate 2 0 liquid Vinegar 0, + Stearate 18 0 solid Beef fat Linoleate 18 2 liquid Oils + 13 Trans Fatty Acids 14 Trans fatty acids can be created during food processing by hydrogenation. Hydrogenation causes some double bonds to become saturated. Hydrogenated fats can be found in
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This note was uploaded on 09/28/2011 for the course NST 10 taught by Professor Amy during the Fall '08 term at Berkeley.

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Lectures 6 _ 7 - Lipid Digestion _ Absorption B_W - Lipids...

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