The Lipids: Triglycerides, Phospholipids, and SterolsIntroductionLipid DefinitionsFats and OilsPowerPoint PresentationHealthy FatsQualified Health Claim- NutsSlide 8Slide 9Slide 10Slide 11Slide 12Chemist’s View of Fatty Acids and TriglyceridesSlide 14Slide 15Slide 1618-Carbon Fatty AcidsOmega-3 and Omega-6 Fatty Acids Compared (Polyunsaturated)Fatty Acid Composition of Common Food FatsHydrogenationSlide 21Cis- and Trans-Fatty Acids ComparedChemist’s View of Phospholipids and SterolsLecithinSlide 25The Lipids: The Lipids: Triglycerides, Triglycerides, Phospholipids, and Phospholipids, and SterolsSterolsChapter 5 (Lecture #1)Chapter 5 (Lecture #1)Dr. Alisha RovnerDr. Alisha RovnerUniversity of DelawareUniversity of DelawareNutrition Concepts (NTDT200)Nutrition Concepts (NTDT200)Fall 2013Fall 2013IntroductionIntroduction•Macronutrient (9kcal/gram)•Fats are important component in the diet. Only when too much or too little fat is consumed does poor health develop•ADMR: 20-35% kcalories from fat•Fats are composed of carbon (C), hydrogen (H) and oxygen (O) but compared to carbohydrates they have more C & H in proportion to OLipid DefinitionsLipid Definitions•Family of compounds that include:TriglyceridesPhosopholipidsSterols• Characterized by their insolubility in waterFats and OilsFats and OilsFats- Lipids that are solid at room temperature.Oils- Lipids that are liquid at room temperature.p149Healthy FatsHealthy FatsWell-balanced, healthy meals provide some fat with an emphasis on monounsaturated and polyunsaturated fats.Healthy FatsHealthy FatsPeople who eat nuts as part of a heart-healthy diet can lower the LDL, low-density lipoprotein or "bad," cholesterol level in their blood. High LDL is one of the primary causes of heart disease.Qualified Health Claim- NutsQualified Health Claim- Nuts•Scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease.p160Healthy FatsHealthy FatsLimited and not conclusive scientific evidence suggests that eating about 2 tablespoons (23 grams) of olive oil daily may reduce the risk of coronary heart disease due to the monounsaturated fat in olive oil. To achieve this possible benefit, olive oil is to replace a similar amount of saturated fat and not increase the total number of calories you eat in a dayQualified Health Claim- Olive oilQualified Health Claim- Olive oilHealthy FatsHealthy Fatsp150A double bacon cheeseburger, fries, and milkshake has 1600 kcalories 90 grams of fat and more than 30 grams of saturated fat—far exceeding dietary fat guidelines for the entire day. Saturated fats tend to raise “bad” (LDL) cholesterol levels in the blood, which in turn increases the risk for heart disease. Unhealthy FatsUnhealthy FatsTable 5-2 p138Lipd amiLipid FamilyLipid FamilyChemistChemist’’s View of Fatty Acids s View of Fatty Acids and Triglyceridesand Triglycerides•Fatty acids •Chain of carbon atoms with hydrogens attached- methyl group (CH3) at one end and acid group (COOH) at other end•Usually even number of carbons•18-carbon fatty acids abundant in food•Saturations•Saturated – full of hydrogens•Unsaturated – missing hydrogensFigure 5-2 p133When glycerol is free, an Oh group is attached to each carbon. When glycerol is part of a triglyceride, each carbon is attached to a fatty acid.GlycerolFigure 5-3a p133Condensation of Glycerol and Fatty Acids to Form a Triglyceridep13018-Carbon Fatty AcidsMethyl endAcid end A saturated fatty acid carries the maximum # of H18-Carbon Fatty AcidsOmega-3 and Omega-6 Fatty Acids Compared (Polyunsaturated)Fatty Acid Composition of Common Food FatsHydrogenationHydrogenation•Chemical process by which hydrogens are added to mono or polyunsaturated fatty acids to reduce the # of double bonds, making the fats more saturated (solid).•Two advantages:•Protects against oxidation prolonging shelf life•Improves texture of foods (ie. makes margarines spreadable.HydrogenationHydrogenationCis- and Cis- and TransTrans-Fatty Acids -Fatty Acids ComparedComparedChemistChemist’’s View of s View of Phospholipids and SterolsPhospholipids and Sterols•Phospholipids•Solubility in fat and water•Emulsifiers in food industry•Lecithin•Food sources•Roles•Part of cell membranes•EmulsifiersLecithinChemistChemist’’s View of s View of Phospholipids and SterolsPhospholipids and Sterols•Sterols•Food sources•Cholesterol•Plant sterols•Roles of sterols•Body compounds made from
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