第一章植物学基础3营养与食品卫生PPT.ppt

脂类 （Lipids）;In the fall of 1995 when 28-year-old skater Sergei Grinkov, a two-time Olympic gold medalist, collapsed and died of a fatal heart attack while training in Lake Placid, New York.;Main contents;An autopsy revealed that his coronary arteries were as severely clogged as those of a 70-year-old with established heart disease.;High fat diet; Can you talk about something related with lipid or fat?;Lipid: A diverse group of organic substances that are insoluble in water; lipid include triglycerides, phospholipids, and sterols. ; Organic: to describe foods that are grown without the use of non-natural fertilizers or chemicals. Organic: These nutrients contain the element carbon. ;95%; 甘油三酯的分子结构Molecular structure of triglycerides ;Most of the fat we eat (95%) is in the form of triglycerides, the same way by which most of the fat in our body is stored. 甘油三酯既是食物中脂肪的主要存在形式，也是机体内脂肪的主要贮存形式;磷脂（Phospholipids）: A type of lipid in which a fatty acid is combined with another compound that contains phosphate; unlike other lipids, phospholipids are soluble in water.;磷脂主要贮存在脑、神经和肝脏中； 磷脂是构成细胞膜的主要成分； 磷脂的主要功能有：提供能量；具有极性和非极性双重特性，有助于物质转运；作为乳化剂，有利于脂溶性物质的吸收、转运及代谢；转运血液中的脂类物质，防治胆固醇在血中的沉积；促进和改善神经系统功能。;A type of lipid found in foods and the body that has a ring structure; these multiple-ring structure is quite different from that of triglycerides.;Sterols;Cholesterol is only found in the fatty part of animal products such as butter, eggs, whole milk, meats and poultry（胆固醇只存在于动物性食品中）. We don’t need to consume cholesterol in our diet because our body continually synthesizes it, mostly in the liver and intestines （机体能够合成胆固醇）. Too much consumption is harmful。（胆固醇摄入过多对人体有害）;Cholesterol is part of every cell membrane, where it works in conjunction with fatty acids to help maintain cell membrane integrity （保持细胞膜的完整性）. Cholesterol is particularly plentiful in the neural cells that make up our brain, spinal cord, and nerves （神经细胞中含量丰富，参与脑、脊髓和神经等的形成）.;The body also uses ch