藜麦麸皮蛋白的氨基酸分析及营养价值评价

Amino Acid Analysis and Nutritional Evaluation of Quinoa Bran Protein

采用全自动氨基酸分析仪对藜麦麸皮蛋白的氨基酸进行检测。藜麦麸皮蛋白中Asp、Glu、Leu、Arg的含量较高,Cys、Met的含量相对较低。总蛋白和清蛋白的氨基酸构成无差异性;醇溶蛋白富含疏水性氨基酸,特别是Pro,Tyr相对缺乏;球蛋白含有较高的Lys;谷蛋白含有较低的Cys。藜麦麸皮总蛋白、清蛋白和谷蛋白的限制性氨基酸是Lys,球蛋白的是Leu,醇溶蛋白的为Ile、Leu、Lys,其中Lys为第一限制性氨基酸,依据FAO/WHO推荐的0.5岁和18岁以上人体必需氨基酸评分模式计算氨基酸评分分别为:63、68、73、83、66和80、86、93、93、82。藜麦麸皮总蛋白和清蛋白的氨基酸比值系数和氨基酸比值系数分与鸡蛋蛋白接近,与其氨基酸构成贴合度达到0.99,优于球蛋白、醇溶蛋白、谷蛋白和大豆分离蛋白;球蛋白与谷蛋白相当,稍好于大豆分离蛋白,醇溶蛋白的营养价值最低。

The amino acids in protein of quinoa bran were detected by Automatic amino acid analyzer.The content of Asp、Glu、Leu、Arg was higher,more than 50 mg/g pro,while the content of Cys and Met was relatively lower,and the lowest were 16.72 mg/g pro and 17.43 mg/g pro,respectively.There was no significant difference in amino acid composition between total protein and albumin of quinoa bran.Prolamin was rich in hydrophobic amino acids,especially Pro,but Tyr was relatively deficient.Globulin contained higher lysine,while glutelin contained lower Cys.Lys was the restrictive amino acid for total protein,albumin and glutelin of quinoa bran,Leu for globulin,and the restrictive amino acids of prolamin were Ile,Leu and Lys,while lys was the first limiting amino acid.According to the FAO/WHO recommended score model of essential amino acids for human body aged 0.5 years and over 18 years,the amino acid scores were 63,68,73,83,66 and 80,86,93,93,82,respectively.The ratio coefficient of amino acid(RC)and score of RC(SRC)of total protein and albumin were similar to egg protein,with the close degree of amino acid composition 0.99,which were better than globulin,prolamin,glutenin and soy protein isolate.Globulin was the same as glutenin,slightly better than soy protein isolate,and the nutritional value of prolamin was the lowest.