食品营养价值分析683幻灯片.ppt
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食品营养价值分析 Weina Tian protein lipids macronutrients carbohydrate (dietary fiber) nutrients water vitamin micronutrients macroelements minerals 核酸 nucleic acid ? microelements 含量----16%——19%. 更新: 动态平衡,不断更新,每天约3%,肠和骨髓最快。 1. 种类:20种 (1) 必需AA(EAA) (2) 非必需氨基酸(NEAA) (3) 半必需氨基酸 ( semi-EAA or conditional EAA) 半胱酸(Cysteine)——蛋氨酸(Methionine) 酪氨酸(Tyrosine)——苯丙氨(Phenylalanine) 2. 必需氨基酸: 人体不能合成或合成速度不能满足机体需要,必需从 食物中直接获得的AA。 Amino acids that the body cannot synthesize in amount sufficient to meet physiological needs and has to obtain them from foods. 氨基酸模式(AA Pattern)和限制氨基酸 (limiting AA) 1. 氨基酸模式 (AA Pattern) : 蛋白质中各种必需氨基酸的构成比例。 2. 限制氨基酸(limiting amino acid): 与人体蛋白质模式比较,食物蛋白质中含量相对较低的必需AA。 The essential amino acid found in the shortest supply relative to the amount needed for protein synthesis in the body. 3. 参考蛋白、完全蛋白和蛋白质的互补作用 几种食物混合后蛋白质的生物价 氮平衡(Nitrogen balance) (1)必要的氮损失(obligatory nitrogen losses) (2) 氮平衡: B=I-(U+F+S) 食物蛋白质营养学评价 (1)真消化率(true -) 蛋白质利用率(utilization) 1.Biological value, BV:生物价 Net Protein Utilization, NPU 蛋白质净利用率 The amount of protein nitrogen that is retained from a given amount of protein nitrogen eaten. To determine the amino acid composition and digestibility of a test protein. Protein Efficiency Ratio, PER: 蛋白质功效比值 A measure of protein quality assessed by determining how well a given protein supports weight gain in growing rats. Used to establish the protein quality for infant formulas and baby foods. Amino Acid Scor
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