不同品种抹茶营养物质和抗氧化活性的测定及主成分分析

Determination of nutrients and antioxidant activities of different varieties ofmatcha and their quality evaluation using principal component analysis

为研究不同品种抹茶在相关基础理化指标、营养物质和抗氧化活性上的品质差异,以8种不同品种(国内5种,国外3种)抹茶为研究对象,系统地比较不同品种抹茶中水分、水浸出物、粒度(D60)、灰分、可溶性蛋白、可溶性糖、茶氨酸、茶多酚、儿茶素类化合物、咖啡碱和体外抗氧化活性的差异,并通过主成分分析建立抹茶品质评价模型。主成分分析结果表明,共提取出2个主成分,累积方差贡献率可达82.5%。所有抹茶的水分、粒度(D60)和灰分均符合GB/T 34778—2017《抹茶》的要求。我国不同品种抹茶的水浸出物、可溶性蛋白、可溶性糖、茶氨酸、茶多酚、表没食子儿茶素没食子酸酯和咖啡碱含量均显著高于国外抹茶样品(P<0.05)。此外,“龙井43”品种抹茶的综合体外抗氧化活性最强,综合品质评分也最高。

To study the quality of different varieties of matcha in related basic physicochemical indicators,nutrients,and antioxidant activities,8 different varieties of matcha(5 domestic varieties and 3 foreign varieties)were used as the research objects.The differences in moisture,water extract,particle size(D60),ash,soluble protein,soluble sugar,theanine,tea polyphenols,catechins,caffeine,and in vitro antioxidant activities in different varieties of matcha were systematically compared,and the matcha quality evaluation model was established through principal component analysis(PCA).A total of 2 principal components were extracted from the results of PCA,and the cumulative variance contribution rate reached 82.5%.The moisture,particle size(D60),and ash content of all matcha met the requirements of GB/T 34778—2017 Matcha.The contents of water extract,soluble protein,soluble sugar,theanine,tea polyphenols,epigallocatechin gallate,and caffeine in different varieties of domestic matcha were significantly higher than those in foreign matcha samples(P<0.05).Moreover,the“Longjing 43”variety of matcha had the strongest antioxidant activity in vitro and the highest comprehensive quality score.