72份青稞氨基酸组成与营养价值评价

为了解青稞氨基酸的组成及营养品质,本研究测定了72份青稞材料籽粒的17种氨基酸(色氨酸除外)含量,通过对供试青稞材料氨基酸含量进行聚类分析,并比较育成品种与地方品种的氨基酸组成差异,对青稞的氨基酸进行了营养价值评价。结果表明,青稞氨基酸总含量平均为87.454 mg/g DW,变幅为47.8~178.7 mg/g DW,其中必需氨基酸含量占37.15%,谷氨酸的含量最高且变异大,蛋氨酸含量最低,赖氨酸含量变异小,91.67%的青稞材料的第一限制性氨基酸为赖氨酸。青稞氨基酸的贴近度为0.903,与世界粮农组织(FAO)、世界卫生组织(WHO)、联合国大学(UNU)提出的模式蛋白质的必需氨基酸组成较接近,氨基酸比值系数分SRC(73.14)较高。非必需氨基酸占青稞总氨基酸含量的62.85%,其中鲜味和甜味氨基酸含量分别为26.58 mg/g DW和21.85 mg/g DW,分别占总氨基酸含量的30.04%和24.43%。不同青稞材料的氨基酸含量和营养价值有很大的差异,地方品种各氨基酸含量均高于育成品种。供试材料中有4份青稞的氨基酸营养价值及风味氨基酸含量均较高。研究结果可为优质氨基酸组成的青稞选育及青稞加工提供指导。

Evaluation of the Amino Acids Composition and Nutrition Value of 72 Hulless Barley

In order to make better use of Tibetan hulless barley,the content of 17 amino acids(except tryptophan)for 72 hulless barley accessions was determined,and the nutritional value and flavor of amino acids was evaluated by WHO/FAO/UNU model.The cluster analysis was performed using the amino acid composition,and the difference of nutrition between landraces and modern varieties was surveyed.The total content of amino acids in hulless barley was 87.454 mg/g DW,with a range from 47.8 to 178.7 mg/g DW.The indispensable amino acid accounted for 37.15%,which was higher than that of oat,hulled barley and wheat.The Tibetan hulless barley exhibited the highest content(23.27%)of glutamine with large variation(CV=33%),and the lowest methionine(1.75%).The composition of amino acids in Tibetan hulless barley was similar to that in hulled barley and wheat.The Tibetan hulless barley had higher content of lysine compared with other cereal crop grains.The close degree U of hulless barley was 0.903,and 69.44%of the tested accessions was more than 0.900.That indicated that the composition of indispensable amino acid of Tibetan hulless barley were close to the model protein and thus had higher nutritional value.The Tibetan hulless barley genotypes presented broad variation on the sum of dispensable amino acids(28.7-118 mg/g DW),with the average of 55.785 mg/g DW.The content of amino acid contributing freshness was 26.58 mg/g DW and that for sweetness was 21.85 mg/g DW.For nutrient balance,hulless barley was higher among cereal crops,the value of Score of Ratio Coefficient was 73.14.The content of amino acids in landraces/historic varieties was higher than that of improved varieties.Notably,four accessions were identified with the qualified nutritional value and flavor amino acid content.Thus,by unlocking the content of amino acids in hulless barley accessions,this study provided valuable insights to select elite genotypes in breeding for high-quality food hulless barley varieties.