Lecture 9 – Main topics LIPIDS : Include Fats, Oils and other compounds (cholesterol, phospholipids, waxes, etc) Fats are (semi)-solids at room temperature. Common sources are meat and dairy products. Oils are liquid at room temperature. Ex.: cooking oils Lipids – many roles- Energy source: 9 kcal/g - Energy storage: they make up most of our fuel reserves. Same for animals, example in foods: Marbling of meat. USDA grading is based on fat distribution (see McGee p.136-8) - Transport of fat soluble vitamins: A, D, E, K. Major roles of fat-soluble vitamins: Vit A - vision Vit E – antioxidant Vit D - bone health Vit K - blood clotting - Supply essential fatty acids - In foods: - sensory appeal - texture, flavor (flavorful volatile compounds dissolve in fat) - heat transfer. Lipids used as cooking medium; Heat transfer with hot oil/fat is called: frying Basic structure of most lipids: TRIGLYCERIDE (TG; Triacylglycerol). TG are the most abundant lipids in the body and in foods. TRIGLYCERIDE contain 3 FATTY ACIDS linked to a molecule of glycerol.
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