【作者】 刘洁；

【导师】 郭兴凤；

【作者基本信息】 河南工业大学 ， 食品科学与工程， 2014， 硕士

【摘要】 玉米蛋白粉是湿磨法生产玉米淀粉的副产物，蛋白含量达60%以上，主要包括醇溶蛋白和谷蛋白。玉米蛋白粉通常作为动物饲料或者肥料使用。目前针对玉米蛋白水解物、玉米谷蛋白水解物和玉米醇溶蛋白水解物的理化性质以及生物活性等方面都有研究，但各水解物抗氧化活性的综合研究鲜见报道。本论文以玉米蛋白粉为原料，从玉米蛋白粉中提取谷蛋白和醇溶蛋白，分别优化了各水解物的制备工艺条件，研究了各水解物的抗氧化能力，探究了各水解物的分子大小与抗氧化能力之间的关系。分别用碱性蛋白酶、中性蛋白酶和木瓜蛋白酶水解制备玉米蛋白水解物，确定了碱性蛋白酶水解效果最佳。通过单因素和响应面试验确定了制备玉米蛋白水解物、玉米谷蛋白水解物和玉米醇溶蛋白水解物的最佳工艺条件。制备玉米蛋白水解物的最佳水解工艺条件为加酶量3.13%，pH值8.6，水解时间4.3h，水解温度56℃，底物浓度1%，在此条件下测得水解产物的还原力为0.617；制备玉米谷蛋白水解物的最佳水解工艺条件为加酶量3.35%，pH值8.3，水解时间4.15h，水解温度56℃，底物浓度1%，在此条件下测得水解产物的还原力为0.673；制备玉米醇溶蛋白水解物的最佳水解工艺条件为加酶量2.33%，pH值8.3，水解时间4.3h，水解温度58℃，底物浓度1%，在此条件下测得水解产物的还原力为0.496。对最优条件下获得的玉米蛋白水解物、玉米谷蛋白水解物和玉米醇溶蛋白水解物进行抗氧化活性研究，分别研究了水解度、水解产物浓度与抗氧化活性的关系。结果表明，水解度的变化同抗氧化评价指标的变化并不完全符合对应关系，而水解产物的浓度与抗氧化活性之间呈较好的量效关系。另外，通过比较IC50值，得出玉米蛋白水解物清除DPPH和O2-能力优于其它两种水解物，但其清除能力不如抗坏血酸；玉米醇溶蛋白水解物清除OH能力优于其它两种水解物，同时三者的清除能力均优于抗坏血酸。为进一步研究玉米蛋白水解物的抗氧化活性与分子大小之间的关系，采用SephedaxG-25凝胶过滤色谱对玉米蛋白水解物进行分离纯化。确定了凝胶过滤色谱的最佳分离纯化条件为：洗脱速度45mL/h，样品浓度0.1g/mL和样品体积2mL，在此条件下将玉米蛋白水解物分为3个组分A1、A2和A3，三者的峰面积比依次为14.4%、17.9%和38.2%。通过测定各分离组分的抗氧化指标，得出A3组分的抗氧化能力最强。更多还原

【Abstract】 Corn gluten meal, by-product of corn starch processing, contains more than60%protein.Zein and glutelin are the primary protein components, So far corn gluten meal is mainly usedas animal feed and fertilizer. Physicochemical properties and bioactivities of corn glutenhydrolysates, glutelin hydrolysates and zein hydrolysates have been researched, but researchabout the systematic comparison of antioxidant activities among those hydrolysates has beenreported rarely. In this thesis, corn gluten meal was used as materials to extrect glutelin andzein. The enzymatic hydrolysis conditions of three proteins were optimized by responesurface methodology. The antioxidant activities of the hydrolysates were investigated, and therelationship between molecular mass of the hydrolysates and antioxidant activities wasanalyzed.Three proteases (Alcalase, Neutral protease and Papain) were choosed to hydrolyze corngluten meal, the result showed that hydrolysates prepared by Alcalase have the bestantioxidant activity. Then the enzymatic hydrolysis conditions of corn gluten, glutelin andzein hydrolyzed by Alcalase were optimized by single factor experiment and response surfacemethodology. The optimum enzymatic hydrolysis conditions of corn gluten were: enzymeamount3.13%, pH8.6, hydrolysis time4.3h, hydrolysis temperature56℃, substrateconcentration1%, and under these conditions, the reducing power of corn gluten hydrolysateswas0.617; The optimum conditions of glutelin were:3.35%,8.3,4.15h,56℃,1%,respectively, and under these conditions, the reducing power was0.673; The optimumconditions of zein were:2.33%,8.3,4.30h,58℃,1%, respectively, and under these conditions,the reducing power was0.496.Antioxidant activities of corn gluten hydrolysates, glutelin hydrolysates and zeinhydrolysates prepared under the optimum conditions were also discussed. The relationshipbetween the degrees of hydrolysis (DHs) and antioxidant activities, and the relationshipbetween concentrations of those hydrolysates and antioxidant activities were estimated. Theresults indicated that DH had no corresponding relation with antioxidant activities, butconcentrations of those hydrolysates had a dose-dependent relationship with antioxidantactivities. By comparing IC50, the DPPH and O2-scavenging activities of corn glutenhydrolysates were better than glutelin and zein hydrolysates, while DPPH and O2-radicalscavenging activities of the three hydrolysates were all lower than ascorbic acid. The OH scavenging activity of zein hydrolysates was better than corn gluten and glutelin hydrolysates,and OH scavenging activity of the three hydrolysates were better than ascorbic acid.In order to explore the relationship between antioxidant activities and molecular mass ofcorn gluten hydrolysates, sephedax G-25gel filtration chromatography was used tofractionate corn gluten hydrolysates. The optimum conditions of gel filtration chromatographywere: flow rate45mL/h, sample concentration0.1g/mL, sample volume2mL. Three fractions(A1, A2and A3) were obtained under the optimum conditions, and the peak area ratios offractions were14.4%,17.9%and38.2%, respectively. The antioxidant activities of thosefractions were determined, and found out that A3has the best antioxidant activities.更多还原