04 第四章 Protein Nutrition.ppt

第1页：蛋白质营养封面

Protien Nutrition

第2页：蛋白质代谢回顾

Review:Protein Metabolism

第3页：蛋白质化学功能回顾

Review:Protein Chemical Function

第4页：氨基酸缩合与肽链形成

氨基酸缩合肽链延长蛋白质亚基形成

第5页：蛋白质的概念与命名由来

§1 Concept

Definition

Protein is the life base Complex of 20 Amino Acids (AA) in body

Named

1836 Chemist Muldgr (柏采里.乌斯 Sweden) found 1888 Berzelius named 1852-1919 Emil Fischer (Germany) ，建立有机结构化学和蛋白质分析法，1902 年获诺贝尔化学奖, 1907 年合成 18 个 AA 的肽链。

第6页：蛋白质的元素组成与更新

Composition

Main Elements

C, H, O, N

Fewer Others

S, Fe, Cu----

Content in Body

16-19%

Renew

3% in a day (20g Prot. or 3.2g N)

Exchange

1/4 in total Surviving 30-50d when starving

第7页：蛋白质测定：凯氏定氮法

Analysis Method (GB)

• kjeldehl
• CP% = N×6.25

第8页：蛋白质的生理功能

§2 Protein function & classification 1 Function

Composition in Body

Muscle, Blood plasma

Physiological Actives

Enzymekeeping osmosis

Supplying Energy

1g = 4kcal/g = 16.7k J/g

第9页：蛋白质的分类

2 Classification

按 EAA

完全蛋白半完全蛋白不完全蛋白

按结构和溶解度

简单蛋白硬蛋白结合蛋白

第10页：食物蛋白质的营养学分类

营养学上按氨基酸种类与数量把食物蛋白质分为三类

完全蛋白质

优质蛋白质，必需氨基酸种类齐全、数量充足、比例适当，既维持人体健康又促进生长发育，如奶、蛋、鱼、肉中的蛋白质。

半完全蛋白质

氨基酸种类齐全但某些氨基酸数量不足，可维持生命但不能促进生长发育，如小麦中的麦胶蛋白含赖氨酸很少；含量相对不足的氨基酸称为限制氨基酸，谷类蛋白质的限制氨基酸多为赖氨酸。

不完全蛋白质

不能提供人体所需的全部必需氨基酸，单纯依靠既不能促进生长发育也不能维持生命，如肉皮中的胶原蛋白。

第11页：参考蛋白

4 Reference Protein Egg Human milk These AA pattern are similar to human AAP

第12页：

第13页：按氨基酸侧链电荷分类

Classification 1 According toα-AA chain -NH3+, -COO-Alkali Neutral Suppl.Acid

第14页：按营养重要性分类

Classification 2 According to Nutritional important

• Essential Amino Acid (EAA)
• Limiting Amino Acid (LAA)
• Non-Essential Amino Acid (NEAA)

第15页：必需氨基酸EAA

Essential Amino Acid (EAA):(8+1) Leucine (Leu, 1st 1810) Isoleucine (Ile) Lysine (Lys) Methionine (Met) Phenylalanine (Phe) Threonine (Thr,last 1935) Trypotophane (Try) Valine (Val) Histidine (His for Infant) Knownas 1983 We need them from Food, but not made in ourselves

第16页：限制氨基酸LAA

Limiting Amino Acid (LAA)

• Three：Lys, Met, Thr Special for Growing
• Ideal Ratio：Lys: Met: Thr = 100: 60: 40 in Ration
• Amino Acid Pattern：Compared with different kinds, ratio & content between human body and food supplement Trp as 1
• High quality of protein:

第17页：非必需氨基酸与条件必需氨基酸

Nonessential Amino Acid (NEAA) NEAAcan be synthesized from others in body Ala Arg Asp Asn Glu Gln Gly Pro Ser Conditional EAA Cys Tyr When Cys and Tyr were enough in body the requirement of Met and Phe was decreased by 30% and 50% .

第18页：氨基酸模式与互补作用

Amino Acid Pattern (AAP) Complementary Actionof Protein/Amino Acidscan be access tobody protein patternfrom various foodstuffs Such as : beef/ Pork + Corn/ Rice Bio-value Lys Met + Cys 1 The amino acid values for the pattern are expressed on a per-gram-of-nitrogen basis 2 The amino acid patterns and the total nitrogen content were used to calculate the levels of individual amino acids per 100 g of food

第19页：混合膳食蛋白质生物价示例

混合膳食提高蛋白质生物价（BV）示例

单一天然食物的BV分别为：玉米60、面粉67、大豆64、小米57；限制氨基酸互补后混合膳食BV升至70与89。表中「—」表示该组合未使用此种食物。

第20页：氮平衡与平衡膳食导览

• Balanced Diet
• Nitrogen Balance Suppl.§4 Nitrogen Balance & Balanced Diet

第21页：理想蛋白与平衡膳食

1 Balanced Diet Hypothesis of Ideal Protein

• The number of EAA is enough
• The ratio of AA is suitable from foodstuffs
• Various foodsources A set of values that serve as the pattern for calculating the amino acid profile of other similar foods

第22页：氮平衡

2 Nitrogen Balance

• Definition：N-intake is equal to N-ejection every day keeping weight for adults
• Index NB= N-intake -N-ejection (Urine + Feces + Skin)1.Zero Nitrogen Balance：N-intake = N-ejection 2.Positive Nitrogen Balance：N-intake > N-ejection 3.Negative Nitrogen Balance：N-intake < N-ejection Notes: ONL≈3.2g/d (×6.25) Protein Loss≈20g/d (= 16%×N) Obligatory Nitrogen Loss/ ONL/必要的氮损失

第23页：食物蛋白评价：含量与消化率

§5 Nutritional Evaluation for Foods 1

• CP or AA content (Ratio of EAA : CP)
• CP Digestibility 1 Apparent Digestibility:(Protein in food -Protein in feces ) ÷Protein in food ×100%2 True Digestibility*:(Protein in food -Protein in Control) ÷Protein in food ×100% P14-16

第24页：生物价BV与净利用率NPU

• Nutritional Absorptivity：Percentage of Nutrients in Gut
• Biological Value (BV)*BV=Food N-(FN+UN)/ Food N-FN100%
• Net Protein Utilization (NPU) NPU= DigestibilityBV= UN-En N/Food N100 Nutritional Evaluation for Foods 2

第25页：蛋白质功效比值PER

Protein Availability or Efficiency

• Percentage of change and synthesis into new tissue Body Weight Gain÷Protein in food ×100% Body Weight Gain÷a kind of food ×100% Data tested from animal , no human P16 top

第26页：蛋白质需要量与供给量

§5 P-requirement & Supplement 1

Basic requirement

30g CP/d for adult

Safety Supplement

0.8g/kg.d (48-56g/d)

Recommendation

1.16g/kg.d (70-90g/d) RDA: 72g/d

CP in Energy

10-12% (P: E) for adult 12-14% for childrange: 10-20%(15-20) P18

第27页：蛋白质食物来源的选择

P-Supplement 2 From foods at all

• Food Protein Source 1 Protein content >15%eg: meat, egg, soybean 2 Better Protein Sourceeg: as above

第28页：各类食物蛋白质含量

各类食物蛋白质含量与供给比例

优质蛋白来源：肉、蛋、鱼、禽、奶、大豆；膳食中供给比例40-50%，蛋白质供能比15-20%。

第29页：蛋白质营养不良表现

Malnutrition P17-18

• Low-protein in blood(albumin 35-50g/L)
• Dropsy
• Marasmus Examplesin Nutritional Evaluation & Anthropometry P197-205

第30页：蛋白质缺乏与过量

Deficiency or Surplus

Deficiency

Dropsy& Marasmus

Surplus

Over acid in body Accumulating NH4 +, Cr Overload of liver & kidney

第31页：人体蛋白质营养评价

Protein Evaluation for Human

• Arm Circle
• Albumin in serum
• Urine、Cr、BUN

第32页：蛋白质营养思考题

Question 1 What is protein？2 Water is referent protein?3 Which food is the source of better protein？4 What and how many are EAA ？5 What is LAA？Why？6 What is AA pattern？7 How to increase bio-value of food protein？8 What is N-balance Hypothesis？9 Which effects are on protein utilization？10 What is protein support problem？