玉米低聚肽硒螯合物的理化性质及稳定性

Physicochemical Properties and Stability of Selenium-chelating Corn Oligopeptide

以玉米低聚肽和亚硒酸钠为原料制备玉米低聚肽硒螯合物,对其水分、酸溶蛋白、总氮(粗蛋白)、分子量分布进行了考察,然后以螯合态的硒含量和分子量分布为指标,研究了螯合物对温度、pH、消化方式的稳定性,结果表明:玉米低聚肽硒螯合物的螯合率为54.25%±0.24%,得率为53.02%±0.17%,水分含量为7.46%±0.07%,酸溶蛋白含量为16.38%±0.03%,总氮含量为21.17%±0.35%,分子量低于1000 u的比例为85.1512%。在25～100℃环境下,分子量低于1000 u的比例变化不超过7%,硒含量最低不小于70%;在pH=2～12的环境下,分子量低于1000 u的比例变化最高不超过16%,硒含量最低仍在75%以上;在经过胃蛋白酶、胰蛋白酶和两种酶的消化后,分子量低于1000 u的比例分别增加5%、7%和8%,硒含量最低仍在70%以上。这说明玉米低聚肽硒螯合物具有一定的热稳定性、酸碱稳定性和消化稳定性。

Selenium-chelating corn oligopeptide was prepared by using corn oligopeptide and sodium selenite. The basic physical and chemical properties of moisture,acid soluble protein,total nitrogen and molecular weight distribution were analyzed.Taking the molecular weight and selenium content as indicators,the effects of temperature,pH and simulated gastrointestinal digestion in vitro were investigated. The results showed that the chelating rate was 54.25% ± 0.24%,the yield was 53.02 ± 0.17%,the moisture content of the product was 7.46% ± 0.07%,the content of acid soluble protein was 16.38% ±0.03%,the total nitrogen content was 21.17% ± 0.35%,and the molecular weight below 1000 u was 85.1512%. At the temperature of 25~100 ℃,the proportion of molecular weight less than 1000 u changes no more than 7%,and the content of selenium was not less than 70%.In the pH = 2~12,the maximum change of the ratio less than 1000 u was no more than 16%,and the content of selenium was not less than 75%. After digested with pepsin,trypsin and the two enzymes together,the molecular weights less than 1000 u exceed 5%,7% and 8%,and the selenium content was more than 70%.This results showed that selenium-chelating corn oligopeptide had a certain stability in thermo,pH and digestion.