【作者】 高素蕴；

【导师】 郭康权； 潘思轶；

【作者基本信息】 西北农林科技大学 ， 农业生物环境及能源工程， 2003， 硕士

【摘要】 我国大豆种植已有4700多年的历史，大约在19世纪后期才传至欧美各国，目前大豆栽培已遍及世界各国。大豆的用途极为广泛，不仅是主要油料作物，亦是植物蛋白质的主要来源，此外在工业上可用作生产肥皂、甘油、硬化油等重要原料，其副产品豆粕还是畜禽的重要蛋白质饲料。酶水解大豆分离蛋白(SPI)后制得的小分子多肽不仅具有多种功能特性，还能够促进锌的吸收利用。本文研究比较了四种单一酶和三种复合酶分步水解SPI制备小分子大豆多肽的工艺条件，选出最佳的组合，考察了得到的小分子肽与醋酸锌螯合制备多肽锌盐的工艺条件，并探讨了大鼠对多肽锌的生物利用率和多肽锌体内抗氧化性能。研究结果如下： 1、通过酸热预处理对酶水解SPI效果的研究发现，酸处理组水解度的大小与酸的浓度成正比。用0.2N酸与热处理时，2709蛋白酶组DH分别为16.68％与29.89％；2709+AS1.398为42.11％和44.37％；2709+木瓜蛋白酶为37.78％和43.47％，因此热处理比酸处理效果好。 2、通过对四种单一酶和三种复合酶水解SPI效果的试验发现，单一酶水解能力大小为：Flavourzyme＞2709＞木瓜酶＞As1.3920；复合酶分步水解能力大小为：2709+Flavourzyme＞木瓜酶+2709＞As1.398+2709；除Flavourzyme组合水解外，复合酶水解能力均高于各自单一酶水解能力。 3、对酶水解产物分子量分布研究结果表明，酶水解产物中中低分子量肽含量，Flavourzyme组＞木瓜蛋白酶+2709＞2709+As1.398＞2709。由于2709+As1.398产物分布更有区域性，因此选用它为多肽锌螯合盐的多肽来源。 4、多肽锌螯合物制备的最佳条件是：多肽反应液浓度4％，肽锌质量比2.25：1，pH值为5.0，温度60℃，时间40min。 5、肽锌螯合盐的溶解度随着溶剂极性的增加而增大，在pH4的水中溶解度最大，为1.055(g/L)。 6、经高效液相色谱分析，多肽锌螯合盐主要有10个级份。经过初步的紫外扫描，红外分析知，多肽锌螯合盐与多肽和锌原不同，是一种新型螯合物； 7、补充不同锌源和剂量锌对缺锌大鼠肝重、肾重、脑重、睾丸重的影响无显著差异；补充多肽锌可显著增加缺锌大鼠脾重。 8、补充多肽锌组，脂肪含量较低，说明多肽锌具有一定的减肥效果。 9、多肽锌螯合盐能较好地促进机体锌吸收利用。补充20ppm多肽锌螫合盐的效果优于补充40ppm葡萄糖酸锌组、蛋氨酸锌和硫酸锌的效果。补充高剂量多肽锌螯合盐对缺锌大鼠AKP活力影响明显高于其他组，且多肽锌螯合盐组剂量与碱性磷酸酶活性成正比。10、与对照组相比，补充中、高剂量多肤锌组的大鼠的肝组织匀浆中丙二醛含童最低，超氧化物岐化酶活性最高，血清中总抗氧化能力最高，且成量效关系。说明多肤锌有良好的抗氧化性能。更多还原

【Abstract】 Soybean is one kind of widely distributed agricultural products. Its protein plays an active role in modern food industry and new food resource researches. Relative research shows most of the functional soybean peptides are the low weight mass hydrolysates, and those peptides can improve the absorbability of zinc. This paper studied the optimum hydrolysis conditions of soybean protein with single enzyme and compound enzymes, and the zinc chelating condition with low weight mass hydrolysates. Furthermore the Bio-availavility of peptide-zinc chelate and its antioxidant activity were explored. The results are showed as following:1, Study on the effect of Acid or heat pre-treatment on the DH showed that the heat pre-treatment facilitated enzymatic hydrolysis of SPI by increasing the degree of hydrolysis (DH) than Acid (0. 05N, 0.1N, 0. 2N) pre-treated . 2 , Among the papain , neutral proteinase As1.398, alkaline proteinase 2709, and Flavourzyme, The degree of hydrolysis of Flavourzyme is bigger than 2709, than papain , and As1.398; and 2709+Falvourzyme is bigger than Papain +2709, and Asl. 398+2709. Bisides the 2709+Falvourzyme, both 2709+Falvourzyme and Asl. 398+2709 have the bigger DH than their single enzyme. 3, The result of the study on distribution of hydrolysis says the group of Flavourzyme has more low molecular weight peptides , than Papain +2709, than Asl. 398+2709, or 2709. but because the hydrolysis of Asl. 398+2709 has more clear content than others , so it is choosed as the material of peptide-zinc. 4, The optimum chelating conditions of soybean peptides with zinc acetate is the concentration of peptides is 4%(W/V), the ratio of peptide to zinc 2.25: 1(mol/mol), pH 5.0, temperature 60*C, time 40min. 5, With the polarity increasing of solution , the solubility of peptide-zinc is enhancing; and has the most solubility of 0.1055 g/100ml in water at pH4. 6, High performance liquid chromatography (HPLC) was introduced to analysis the peptides-zinc chelate , and the mobile phase was optimized , the optimumconditions were as follow: Lichrospher C18 column (15cm 4.6mm, 5um); The gradient elution method changed from 5% acetonitrile(0.1% formic acid/ acetonitrile) (V/V) to 60% (0.1% formic acid/ acetonitrile)in twenty minutes; UV detection wavelength: 280nm and 220nm; flow rate:lml/min; column temperature 20 .Injection volume lOul, sensitivity 0.02. under this mobile phase the chelate can be divided to 10 fractions according to the retain time . ultraviolet spectrometry (UV) and infrared spectrometry (IR) indicates the peptide-zinc is a new compound different from zinc acetate and peptide.7, The biological activities of peptide-zinc were analyzed. Among the parallel panel: Zinc sulfate, zinc glucose, zinc met and peptide-zinc , they have no different effect in the weight of Wistar rats’ liver .kidney, brains , and testicle; But organic zinc can improve the weight of spleen, and the groups of peptide-zinc have more great influence than other groups. 8, Because of The groups of peptide-zinc having less fat than other groups, so it indicated the peptide-zinc also has the function of losing weight. 9, The groups supplying peptide-zinc with 20ppm {low dose zinc, LDZ}and 40ppm(high dose zinc, HDZ) zinc have the same zinc aggradation , both of them can improve the zinc utility than other zinc supplements. LDZ has the same effect with the ones with 40ppm, such as Zinc sulfate, zinc glucose and zinc met groups.10, The activity of AKP in HZ is higher than others, and the activity is depend upon the peptide-zinc’ s concentration. The HDZ and 30ppm peptide-zinc (moderate dose zinc, MDZ ) have a lower MDA content , and a higher activity of SOD in liver plasm , the value of T-AOC are also bigger than others . All these indicate that peptide-zinc have the antioxidant activity.更多还原