花生醋浸过程中蛋白质、多肽含量变化及其抗氧化性的研究

实验以醋泡花生为研究对象,考察了不同类别的醋和不同浸泡时间对其抗氧化性的影响,并通过测定浸泡过程中粗蛋白含量和多肽含量的变化,探究抗氧化性与醋花生多肽含量变化的相关性。采用DPPH自由基清除法分别测定了陈醋浸泡的花生及香醋浸泡的花生的抗氧化能力,实验结果显示:花生经过醋液浸渍,抗氧化性在浸泡前期增长显著,后期趋于平缓。2种食醋浸泡的花生抗氧化能力无显著性差异。采用凯氏定氮法及分光光度法测定2种食醋浸泡的花生粗蛋白含量及多肽含量,结果显示:花生醋浸过程中粗蛋白含量下降,多肽含量上升。醋浸第13天时,香醋浸泡的花生粗蛋白含量下降了18.03%,陈醋浸泡的花生粗蛋白含量下降了22.63%。花生醋浸过程中多肽含量变化与抗氧化能力变化趋势基本一致,且陈醋浸泡和香醋浸泡的花生多肽含量分别在第7天和第10天达到峰值,含量分别为(5.38±0.07)g/kg和(3.83±0.11)g/kg。采用玻璃电极法测定花生醋浸过程中醋液pH值的变化,结果显示:醋液pH值上升,且在浸泡前3天上升显著。陈醋浸泡的花生醋液pH值低于香醋浸泡的花生醋液pH值。研究结果显示:花生醋浸过程中抗氧化能力与多肽含量变化趋势基本一致,食醋种类对抗氧化能力变化无显著影响。不同食醋因其pH值不同,浸泡的花生粗蛋白含量及多肽含量变化有所差异。

Changes of Protein,Peptide Content and Antioxidant Activity of Vinegar Soaked Peanuts

In this paper,vinegar soaked peanuts are taken as the research object to investigate the effect of different types of vinegar and different soaking time on the antioxidant property.The correlation between antioxidant property and polypeptide content of vinegar soaked peanuts is explored by measuring the changes of crude protein content and polypeptide content in the soaking process.The antioxidant capacity of peanuts soaked in mature vinegar and peanuts soaked in balsamic vinegar is measured respectively by DPPH free radical scavenging method.The experimental results show that the antioxidant capacity of peanuts soaked in vinegar increases significantly in the early stage of soaking and tends to be flat in the later stage.There is no significant difference in antioxidant capacity of peanuts soaked in the two kinds of vinegar.The content of crude protein and polypeptide of peanuts soaked in the two kinds of vinegar is determined by Kjeldahl method and spectrophotometry.The results show that the crude protein content decreases and the polypeptide content increases.At the 13th day of vinegar immersion,the crude protein content of peanuts soaked in balsamic vinegar decreases by 18.03%,and the crude protein content of peanuts soaked in mature vinegar decreases by 22.63%.The change of polypeptide content of peanuts in the vinegar immersion is consistent with the change trend of antioxidant capacity,and the polypeptide content of peanuts soaked in mature vinegar and balsamic vinegar reaches the peak at the 7th day and the 10th day respectively,with the content of(5.38±0.07)g/kg and(3.83±0.11)g/kg.The pH value of vinegar in peanuts vinegar soaking process is determined by glass electrode method.The pH of peanuts soaked in mature vinegar is lower than that of peanuts soaked in balsamic vinegar.The results show that the antioxidant capacity is consistent with the change trend of polypeptide content,while the variety of vinegar has no significant effect on the change of antioxidant capacity.Because of different pH values of vinegar,the content of crude protein and polypeptide of vinegar soaked peanuts is different.