第一章营养学基础蛋白质精要.ppt

Nutrition 营养 What we eat as well as how much we eat determine our nutrition status to an important extent. 人们的营养状况在很大程度上取决于人们吃什么和吃多少。 Nutrition might be defined as the processes whereby we obtain the essential nutrients and use them to make many other substances our bodies need.营养可定义为一种人们赖以获得必需营养素，并利用这些营养素来制造人体所需其他物质的过程。  Good nutrition implies that we are obtaining from our food all of the essential nutrients in the amounts needed to keep our bodies functioning, and to maintain, optimum health. “Eating the right foods in the right amounts.” 营养良好这一术语是指我们处在从食物中获取为保持机体正常活动和维持最佳健康状况所需的全部必需营养素。 营养良好的最简明的说法是：“适量食用恰当的食物”。 Nutrients : The ingredients that give us nourishment in Food are called nutrients. 具有营养功效的食物成份称为营养素。 营养素是指食物中可给人体提供能量、机体构成成分和组织修复以及生理调节功能的化学成分 nutrients are categorized as fats, proteins, carbohydrates (sugars and starches), minerals and vitamins. 到目前为止营养素可分为脂肪、蛋白质、碳水化合物(糖和淀粉)、矿物质、维生素。 Nutrients might be divided into two general categories based on the amount that we need. 根据人体需要量的不同，营养素分为两大类： what we need in relatively large amounts are macronutrients (carbohydrats, fats, proteins)需要量较大的称为常量营养素（碳水化合物、脂肪、蛋白质）； What we need in relatively small amounts are micronutrients(mineral elements and vitamins),需要量较小的称为微量营养素（矿物质和维生素）。 Contents of this class本节讲述内容 History of protein 对蛋白质的认识历史 Essential Amino Acid** 氨基酸和必需氨基酸 Protein’s Function* 蛋白质的功能 Digestion, Absorption and Metabolism 消化、吸收和代谢 Contents of this class本节讲述内容 Evaluation the Nutrition Value of Food Protein** 食物蛋白质营养学评价 Dietary protein deficiency* 　蛋白质营养不良 Assessment of nutritional status 　机体营养状况评价 Protein Allowance and Food Source* 蛋白质供给量和来源 二、 Amino acid 氨基酸 Nearly an infinite number of proteins could be synthesized from the 20 natural amino acids. 　氨基酸是蛋白质的基本构成单位，构成人体蛋白质的氨基酸有20种 The amino acids are linked in chains through peptide bonds. If a few amino acids-are coined together by peptide bonds the compound is called a peptide. 构成蛋白质的氨基酸之间通过肽键连结 Essential A