3. 参考蛋白、完全蛋白和蛋白质的互补作用 参 考 蛋 白 用于测定食物蛋白质质量的标准蛋白。 Reference Protein: A standard against which to measure the quality of other proteins. 完 全 蛋 白 必需氨基酸模式与人体蛋白质相对一致,能满足机体蛋白质合成 需要的食物蛋白质。 Complete Protein: A dietary protein containing all the essential amino acids in relatively the same amounts that human being required. (including animal protein and soy protein ) Incomplete protein 蛋 白 质 互 补 将两种或两种以上的食物蛋白质混合事用,使不同食物中必需氨 基酸以多补少,从而提高膳食蛋白质的营养价值。 Complementary Protein: Two or more proteins whose amino acids assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other
3. 参考蛋白、完全蛋白和蛋白质的互补作用 参 考 蛋 白 用于测定食物蛋白质质量的标准蛋白。 Reference Protein: A standard against which to measure the quality of other proteins. 完 全 蛋 白 必需氨基酸模式与人体蛋白质相对一致,能满足机体蛋白质合成 需要的食物蛋白质。 Complete Protein: A dietary protein containing all the essential amino acids in relatively the same amounts that human being required. (including animal protein and soy protein ) Incomplete protein 蛋 白 质 互 补 将两种或两种以上的食物蛋白质混合事用,使不同食物中必需氨 基酸以多补少,从而提高膳食蛋白质的营养价值。 Complementary Protein: Two or more proteins whose amino acids assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other
几种食物混合后蛋白质的生物价 食物 BV 混 合 比 例 小米- 67 37 - 31 大米 57 32 40 46 大豆 64 16 20 8 豌豆 48 15 - - 玉米 60 - 40 - 牛肉(干) 76 - - 15 混合后生物价 - 74 73 89
几种食物混合后蛋白质的生物价 食物 BV 混 合 比 例 小米- 67 37 - 31 大米 57 32 40 46 大豆 64 16 20 8 豌豆 48 15 - - 玉米 60 - 40 - 牛肉(干) 76 - - 15 混合后生物价 - 74 73 89
三、蛋白质的消化、吸收和代谢 (一)消化和吸收 (digestion and absorption)
三、蛋白质的消化、吸收和代谢 (一)消化和吸收 (digestion and absorption)
Gastric Juice : 1. Acid– denaturation 2. Pepsin- not highly specific but preferential attack on bonds adjacent to aromatic AA and leucine. 3.Carboxypeptidase- terminal aromatic or branch-chained; arginine or lysine; neutraldietary Protein Panc- elastase(弹性蛋白酶)-arometic AA reatic trypsin(胰蛋白酶)- NH2 - juice chymotrypsine(糜蛋白酶) - lysine, arginine dipeptide , tripeptide and free AA absorbed through the mucosal cells of small intestine peptidase through three active free AA transport systems neutral-,basic- and acidic- . Liver and other organs
Gastric Juice : 1. Acid– denaturation 2. Pepsin- not highly specific but preferential attack on bonds adjacent to aromatic AA and leucine. 3.Carboxypeptidase- terminal aromatic or branch-chained; arginine or lysine; neutraldietary Protein Panc- elastase(弹性蛋白酶)-arometic AA reatic trypsin(胰蛋白酶)- NH2 - juice chymotrypsine(糜蛋白酶) - lysine, arginine dipeptide , tripeptide and free AA absorbed through the mucosal cells of small intestine peptidase through three active free AA transport systems neutral-,basic- and acidic- . Liver and other organs
(二) 代谢与氮平衡(metabolism and nitrogen balance) 1.代谢 摄入蛋白质90克 消 化 道 (30%) 肌肉 (50%) 器官 体液 其它 机体蛋白质 氨基酸池 粪便 10g(1.6gN) 尿 75g(12gN) 其它 5g(0.8gN) (20%) 肠道内源性 蛋白质70g 消化、吸收 蛋白质150g 图1-1 蛋白质代谢及氮平衡
(二) 代谢与氮平衡(metabolism and nitrogen balance) 1.代谢 摄入蛋白质90克 消 化 道 (30%) 肌肉 (50%) 器官 体液 其它 机体蛋白质 氨基酸池 粪便 10g(1.6gN) 尿 75g(12gN) 其它 5g(0.8gN) (20%) 肠道内源性 蛋白质70g 消化、吸收 蛋白质150g 图1-1 蛋白质代谢及氮平衡