摘要本实验以大豆分离蛋白为原料，主要研究其理化特性、基本成分、降血糖肽活性。 在理化特性方面，本实验主要研究了大豆分离蛋白的水合能力、溶解度、粘度以及表 面活性的乳化性能。

大豆分离蛋白的水合能力为 4。6（mL 水/g 蛋白质），具有良好的亲水性和保湿性。 酸碱程度对溶解度有很大影响，酸性条件 pH=2 时，大豆蛋白的溶解度达到 92。3%， 碱性条件 pH=8 时，溶解度为 81。2%，pH=4-6 时，溶解度低于 20%。乳化能力和稳定 性都随 pH 值增大而增大，pH=9 时，乳化能力为 71。7（mL 油/mg 蛋白质），乳化稳 定性为 36。9 。利用 Osboren 分类提取法测定大豆蛋白质组成，大豆蛋白质中以球蛋 白为主，占到 55。2%。通过酶解法制备大豆多肽，以 PNPG 为底物测定 α-葡萄糖苷酶 抑制活力，当多肽浓度为 0。6mg/mL 时，其抑制活力能达到 20%左右。大豆多肽在体 内对 α-葡萄糖苷酶的抑制受温度和酸碱性影响，在人体适宜温度 30℃～50℃之间抑 制活性较高，达到 20%左右，37℃时抑制率为 21。01%；在 pH=2-9 的范围内，其抑制 率保持在 18。65%～19。21%，说明 pH 对抑制率的影响不是十分明显，接近中性时抑 制活力稍高，大豆多肽通过抑制 α-葡萄糖苷酶活性而缓解体内对多糖的吸收，能够有 效降低人体血糖浓度。80726

毕业论文关键字：大豆蛋白；理化特性；降血糖肽；稳定性 

Abstract The basic ingredients, hypoglycemic peptide activity of the soy protein isolate (SPI) were researched in this experiment。 In terms of physical and chemical properties, the hydration capacity, solubility, viscosity and emulsification of SPI were researched。

The result shown that the hydration capacity of SPI was 4。6 (milliliter water per gram protein), which indicated that the SPI has good hydrophilic and moisture。 The SPI’s solubility was 92。3% at the pH value was 2, and the solubility was 81。2% at the pH value was 8。 While as pH value from 4 to 6, the solubility was less than 20%。 As the pH value increased, the emulsifying capacity and stability increased as well。 The emulsification capacity was measured to 71。7, the stability of the emulsion was 36。9。 The protein composition of SPI was determined by the method of Osboren classification and extraction, we found that the principal protein was globulin, which accounted was 55。2%。

The hypoglycemic peptide of SPI by enzymatic preparation, the activity of Alpha-glucose enzyme inhibitory was determined with the substrate of PNPG。 When the peptide concentration was 0。6mg/mL, the inhibition of activity could reach about 20%。 It was influenced by temperature and pH that the alpha-glucose enzyme activity  was inhibited  hypoglycemic  peptide  from  SPI。  The  inhibition  rate  was  about  20%  at   the

temperature ranged from 30℃ to 50℃, the inhibition rate was 21。01% at the   temperature

was 37℃。 The inhibition rate remained at 18。65% to 19。21% at the pH value ranged from 2 to 9, which indicated that the effect of pH on the inhibition rate was not very obvious, and the inhibition of activity was higher when pH closed to neutral。 The speed of the body's absorption of polysaccharides was limited by the hypoglycemic peptide from SPI through inhibiting the activity of Alpha-glucose enzyme, which could reduce the blood glucose

concentration effectively。

Keywords: soy isolated protein; physical and chemical properties; hypoglycemic peptide; stability

目 录

第一章 绪论 - 1

1。1  大豆蛋白研究利用状况  1 

1。1。1  大豆蛋白概述  1 

1。1。2  大豆蛋白的国内外研究现状及其存在问题 - 3