小米蛋白提取及营养评价

Isolation and nutritional characterization of millet protein

为探究小米蛋白提取技术和综合评价小米蛋白的营养价值,采用体外消化法对不同方法提取的蛋白质消化性进行检测,并对小米蛋白氨基酸组成进行分析。结果表明:淀粉酶解法和碱液提取法得到的小米蛋白纯度和蛋白提取率均高于分级提取法;分级提取法和碱液提取法得到的小米蛋白体外消化率均在80%以上,淀粉酶解法提取的混合蛋白体外消化率较低(71.85%);糙小米、碱液提取法和淀粉酶解法提取的混合蛋白PDCAAS分别为42.96、62.33和31.78,第一限制氨基酸均为赖氨酸;分级提取法提取的水溶、盐溶、碱溶和醇溶小米蛋白PDCAAS分别为78.17(Thr)、65.72(Thr)、69.66(Ile)和24.18(Lys);小米蛋白中含有人体所需8种必需氨基酸,E/A大于0.5,E/(A-E)大于1.0,均高于WHO参考蛋白模式,表明小米蛋白是一种优质蛋白。

It was analyzed the amino acid composition and in-vitro protein digestibility (IVPD) to determine isolate technology and nutritional characterization of millet protein.Both protein concentration and extraction rate from millet by α-amylase and alkaline extraction were higher than successive extraction method.The IVPD values by alkaline extraction and successive extract method were more than 80%,but lower by α-amylase (71.85%).The protein digestibility corrected amino acids score (PDCAAS) values of unpolished millet,alkaline extraction and α-amylase were 42.96,62.33 and 31.78 respectively,and the first limited amino acid was Lys.The PDCAAS values of water,salt,alkaline and alcohol solubility protein by successive extraction method were 78.17 (Thr),65.72 (Thr),69.66 (Ile) and 24.18 (Lys),respectively. There are 8 essential amino acids of millet protein.The values of E/A and E/(A-E) are over than 0.5 and 1.0 respectively,higher than WHO recommendation mode,and millet protein is a high quality protein.