燕麦分离蛋白消化特性和消化产物对STC-1细胞分泌胆囊收缩素的影响

为研究燕麦分离蛋白的消化特性及其消化产物对肠内分泌细胞分泌胆囊收缩素(CCK)的影响,以燕麦为原料,采用碱提酸沉法得到燕麦分离蛋白,分析燕麦分离蛋白在模拟胃肠道消化过程中的分子质量变化、氮释放规律、消化产物的氨基酸组成,计算氨基酸评分、化学评分和必需氨基酸指数,并以STC-1细胞为肠内分泌细胞模型评价消化产物对STC-1细胞分泌CCK的影响。实验结果表明:燕麦分离蛋白经胃肠消化后,消化产物的分子质量小于10kDa,释放的可溶性氮的比例为90.11%,消化产物可溶性部分中游离氨基酸的比例为22.8%,肽的比例为67.31%,并且肽的分子质量主要在1000Da以下(约74%)；燕麦分离蛋白消化产物中必需氨基酸总量占38.75%,必需氨基酸与非必需氨基酸的比值为0.63,且必需氨基酸指数(0.95)大于0.90。燕麦分离蛋白消化产物对STC-1细胞影响的实验结果表明,燕麦分离蛋白消化产物对STC-1细胞生长具有显著的促进作用,且能够增加CCK的合成和分泌。研究结果表明,燕麦分离蛋白作为一种优质的蛋白质原料,不仅具有优良的营养功能,而且具有促进肠内分泌细胞分泌CCK的生物活性,在食品领域具有较大的应用潜力。

Digestion Characteristics of Oat Protein Isolate and Effect of Its Digesta on Cholecystokinin Secretion of STC-1 Cells

To explore the digestive characteristics of oat protein isolate and cholecystokinin (CCK) secretion-promoting activity of its digesta, oat was used as raw material to extract oat protein isolate by alkaline extraction and acid precipitation in this study. The relative molecular weight change, nitrogen release and amino acid composition of digesta of oat protein isolate in the simulated gastrointestinal digestion process were analyzed, and the amino acid score, chemistry score and essential amino acid index was calculated. The CCK secretion-promoting activity of digesta was evaluated using STC-1 cells model. The results showed that after oat protein isolate was digested, the relative molecular weight of digesta was less than 10 kDa, and the proportion of soluble nitrogen released increased to 90.11%. In the soluble part of gastrointestinal digesta of oat protein isolate, the proportion of free amino acids and peptides were 22.8% and 67.31%, respectively. The relative molecular weight of peptides was mainly below 1000Da (about 74%). The total amount of essential amino acids in the gastrointestinal digesta of oat protein isolate accounted for 38.75%, the ratio of essential amino acids/non-essential amino acids was 0.63, and essential amino acid index (0.95) was greater than 0.90. The results from STC-1 cells indicated that the digesta of oat protein isolate could significantly promote the STC-1 cell growth, and increase the synthesis and secretion of CCK. These results indicated that as a high-quality protein, oat protein isolate not only had excellent nutritional functions, but also exerted the biological activity of promoting CCK secretion. Oat protein isolate might have great application potential in the food field.