石斛的氨基酸组成及分析

Amino Acids in Dendrobium SW.

利用全自动氨基酸分析仪测定22种主要石斛栽培品种的氨基酸组成和含量,并应用多元统计分析方法对其品质进行分析。结果表明,石斛中以天冬氨酸、谷氨酸、亮氨酸、精氨酸4种氨基酸含量最丰富;蛋氨酸和胱氨酸分别为石斛的第1和第2限制性氨基酸。不同品种石斛的氨基酸含量和组成比例存在一定差异,其中,10种石斛含有17种氨基酸和7种必需氨基酸,11种石斛未检出蛋氨酸或胱氨酸。参照FAO/WHO推荐标准,氨基酸营养价值较高的是线叶石斛、紫瓣石斛、杓唇石斛、玫瑰石斛、紫菀石斛和叠鞘石斛6个品种;采用主成分分析方法和聚类分析,可将22种石斛氨基酸分为4类品质,以石斛氨基酸指标聚类可将22种石斛聚为3类。

The composition and content of amino acids in 22 species Dendrobium were determined by an automatic amino acid analyzer,and multivariate statistics analysis were performed to provide a reference for the quality. The most abundant amino acids were aspartic acid,glutamic acid,leucine and arginine;methionine and cystine were the first and second restricted amino acids in Dendrobium. There was a significant difference in the content of amino acid and the composition. Ten in the 22 species of Dendrobium contained 17 amino acids and 7 essential amino acids. No methionine or cystine was detected in 11 species. D. aurantiacum,D. parishii,D. moschatum,D. crepidatum,D. transparens,D. aurantiacum var. were classified as the richest in amino acids based on the recommendation of FAO/WHO. The amino acids could be divided into four groups by quality with principal component analysis and cluster analysis,and Dendrobium were classified into three categories.