乳清水解及其组分初步测定

文档编号:SW089  文档字数:9764,页数:27

摘要：乳清蛋白属全价优质蛋白，效价高，又具有多种保健功能。近年来研究表明，多种具有生物活性的乳清活性肽，在乳清蛋白应用中发挥了主要作用。为了了解乳清水解多肽的生物活性及其组成，本实验以胰蛋白酶在pH7.0、温度55.8℃、[E/S]3%的最适条件下水解乳清粉，再经过离心处理去除杂质，然后取其上清液用丙酮沉淀法分离多肽，最后自然风干制备得到多肽粉末。采用SDS-PAGE电泳等分析方法对水解产物的分子量分布进行了分析。可知乳清多肽的分子量主要集中在10000以下，特别是在8200～6900之间。氨基酸分析表明，乳清80粉和30粉的氨基酸组成相似。通过滤纸片法测定多肽的抑菌性，目前并没发现多肽有抑菌性。比较凯氏定氮测定水解度、茚三酮比色法测定水解度两种测定方法后，选定后者对乳清水解度的测定，从而得到12～15%的水解度的多肽液。

关键词：乳清粉；乳清多肽；胰蛋白酶；电泳；抑菌性

Whey Hydrolysis and Component Analysis

Abstract: Whey-derived peptides by enzymatic hydrolysis have high nutritional value and many biological functions. It was reported that hydrolysis protein was better to hydrolyze whey protein. The best hydrolysis technology conditions were [E/S]=3%, T=55.8 ℃, pH=7.0. Centrifugal was used after hydrolysis protein. Then, acetone was used to deposit the whey-derived and retrieve hydrolysates. Molecular weight distribution of hydrolysates was analyzed by SDS-PAGE, it was showed that the main molecular weight distribution of whey polypeptide was below 10000, especially between 8200 and 6900. Amino acids of whey-derived was determined. Antimicrobial was studied by filter paper method. The results showed that hydrolysates have no antimicrobial. The degree of protein hydrolysis was measured by ninhydrin colormetric method.
Keywords：Whey; Whey peptides; Trypsin; Electrophoresis; Antimicrobial

目录
中文摘要 I
英文摘要 II
目录 III
1 绪论 1
1.1  乳清蛋白的营养价值 1
1.2  乳清多肽研究国内外现状 2
1.3  本实验研究的目的和意义 2
2. 实验部分 4
2.1  实验材料与设备 4
2.2   方法 5
3 结果讨论 10
3.1  样品电泳结果 10
3.2 液相色谱结果 11
3.3  水解度的测定 13
3.4  氨基酸组分分析 15
3.5  多肽抑菌性研究 17
3.6  本实验讨论 17
4． 总结和展望 19
4.1  总结 19
4.2  展望 19
致谢 20
参考文献 21

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