1 / 31

The Lipids: Triglycerides, Phospholipids and Sterols

The Lipids: Triglycerides, Phospholipids and Sterols. Lipids Objectives. 1. Understand the chemical composition and differences between fats 2. Explain the structural and functional processes of triglycerides, phospholipids, and sterols

rhodess
Download Presentation

The Lipids: Triglycerides, Phospholipids and Sterols

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The Lipids: Triglycerides, Phospholipids and Sterols

  2. Lipids Objectives • 1. Understand the chemical composition and differences between 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

  3. TriacylglycerolTriglycerides R-COO-CH2 R-COO-CH R-COO-CH2 • Triglycerides found in seeds and • animal adipose. • Diglycerides found in plant leaves, • one fatty acid is replaced by sugar • (galactose).

  4. Most Common Fatty Acids in Di- and Triglycerides CH3(CH2)nCOOH

  5. Triglyceride Containing Linoleic Acid Omega-6

  6. Linolenic Acid Omega-3

  7. Fatty Acid Isomers

  8. 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

  9. Lipid Content of Feeds • Forages • Fat content is low: 1 to 4% of dry matter • High proportion of linolenic acid (18:3) • Diglycerides in fats of leaves • Grains • Fat content variable: 4 to 20% of dry matter • High proportion of linoleic acid (18:2) • Triglycerides in oils of seeds

  10. 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)

  11. Fatty Acids are Key Building Blocks • Saturated Fatty Acid • All single bonds between carbons

  12. Monounsaturated Fatty Acid(MUFA) • One carbon-carbon double bond

  13. Polyunsaturated Fatty Acid(PUFA) • More than one carbon-carbon double bond

  14. 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

  15. Degree of Unsaturation • Firmness • saturated vs. unsaturated • Stability • oxidation, antioxidants • Hydrogenation • advantages, disadvantages • Trans-Fatty Acids • from hydrogenation

  16. Hydrogenation

  17. Cis-fatty acid: H’s on same side of the double bond; fold into a U-like formation; naturally occurring; Trans-fatty acid: H’s on opposite side of double bond; more linear; occur in partially hydrogenated foods;

  18. 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

  19. Omega-3 Omega-6

  20. Omega-3 Fatty Acids • Associated with: • anti-inflammatory, antithrombotic, antiarrhythmic, hypolipidemic, vasodilatory properties • Inflammatory conditions • Ulcerative colitis, Crohn’s • Cardiovascular disease • Type 2 diabetes * Mental function • Renal disease * Growth and development

  21. 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 diseases • Depression--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

  22. 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 clot formation, blood lipids, and immune response; --participate in immune response to injury and infection, producing fever, inflammation, and pain; --include:prostaglandins, thromboxanes, leukotrienes

  23. Triglycerides • Structure • Glycerol + 3 fatty acids • Functions • Energy source • 9 kcals per gram • Form of stored energy in adipose tissue • Insulation and protection • Carrier of fat-soluble vitamins • Sensory properties in food

  24. Triglycerides: lipids composed of three fatty acids attached to a glycerol

  25. Triglycerides • Food 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

  26. Fatty Acids in Common Food Fats

  27. Phospholipids • Structure • Glycerol + 2 fatty acids + phosphate group • Functions • Component of cell membranes • Lipid transport as part of lipoproteins • Emulsifiers • Phosphatidylcholine • Food sources • Egg yolks, liver, soybeans, peanuts

  28. Cell membranes are phospholipid bilayers

  29. Sterols: Cholesterol • Functions • Component of cell membranes • Precursor to other substances • Sterol hormones • Vitamin D • Bile acids • Synthesis • Made mainly in the liver • Food sources • Found only in animal foods

More Related