不同固样方法对茶鲜叶主要品质成分的影响

Effect of Preservation Methods on Retention of Main Quality Compnents in Fresh Tea Leaves

为准确反映茶鲜叶生化成分的组成特征,对11个茶树品种鲜叶分别进行冷冻固样、热风固样和微波固样,并通过二维"点集"分布视图和主成分分析,对不同固样方法所获得供试样品的茶多酚总量、游离氨基酸总量、咖啡碱含量、主要儿茶素和游离氨基酸组分进行比较分析。结果表明:热风固样与冷冻固样样品存在较明显的类群区分,且热风固样样品中的茶多酚总量、表没食子儿茶素没食子酸酯、表儿茶素、表儿茶素没食子酸酯、天冬氨酸、精氨酸、丝氨酸、胱氨酸均显著低于冷冻固样;微波固样与冷冻固样无明显的样品类群区分。综合考虑简便性、保真性、节能性等方面,微波固样更适用于茶鲜叶取样制备,其样品生化检测结果可为茶鲜叶质量的化学评价提供参考依据。

Fresh leaves plucked from tea bushes of 11 varieties were preserved by freezing,hot-air drying or microwave heating to compare the retention of polyphenols,free amino acids and caffeine in the leaves.The twodimensional point set distribution and principal component analyses were performed to determine the data variances among the samples.The results showed that the contents of polyphenols,EGCG,EC,ECG,aspartate,arginine,serine and cystine were significantly lower in the tea leaves treated by hot-air than by freezing.Either microwaved or frozen leaves could largely retain the original composition.However,being convenient and efficient in handling and for preservation,the microwave method was recommended for the application.