十六份辣椒材料游离氨基酸组成的主成分分析与聚类分析

为了研究不同辣椒材料中游离氨基酸综合品质的差异,以16份辣椒材料为研究对象,采用液相色谱法测定游离氨基酸种类和含量,利用主成分分析法与聚类分析法进行综合评价。结果表明:辣椒中游离氨基酸含量丰富,含有16~17种氨基酸,总量范围是10.57~25.68 mg·g^-1。种类差异不明显,但是不同辣椒材料之间游离氨基酸含量均存在较大差异,其中,D1的总游离氨基酸、必需氨基酸、限制氨基酸的含量均最高,D4中呈味氨基酸含量最高。通过主成分分析提取到3个主成分(F₁、F₂、F₃),其累计方差贡献率为83.501%,并建立综合评价模型:F=0.775F₁+0.126F₂+0.0969F₃。经综合评价,得分前3位的分别是D4、D1和D2。采用聚类分析方法可将16份辣椒材料分为3类,与主成分分析的结果大体一致,可较好地反映辣椒不同种质间的差异性。

Principal component analysis and cluster analysis for evaluating free amino acids of 16 pepper materials

In order to analyze the differences in the comprehensive quality of free amino acids in 16 different peppers, the free amino acids (FAAs) were determined by liquid chromatography-tandem mass spectrometry, and the systematic evaluation were performed by principal component analysis (PCA) and cluster analysis. The results showed that 16-17 kinds of FAAs were detected in all kinds of peppers, and the total content ranged from 10.57 to 25.68 mg·g^-1. There were significant differences in the contents of free amino acids (FAA), but no obvious difference in species in the 16 cultivars of peppers, among which the highest contents of total free amino acids, essential amino acids, limiting amino acids were observed in the cultivar D1, D4 had the highest content of taste-active amino acids. Three principal components (F₁, F₂, F₃) were extracted by PCA, which contributed cumulatively to 83.501% of the total variance. The comprehensive evaluation model was established as F=0.775F₁+0.126F₂+0.0969F₃. The comprehensive scores of D4, D1 and D2 were ranked as the top three. Cluster analysis was used to divide these daylily cultivars into 3 groups, and the results were consistent with the PCA, which reflected the distinction among different germplasms of peppers.