不同保鲜处理过程中茶青品质成分含量的变化

本研究对采后茶鲜叶进行低温(5~8℃,10~13℃,15~18℃)和常温(21~23℃)处理,通过理化检测分析了茶青品质成分含量在不同保鲜处理过程中的变化情况。结果显示,相较于对照0 h,可溶性糖含量在低温和常温处理36 h中均未发生显著性变化;游离氨基酸含量在10~13℃组中维持着与对照相当的水平;儿茶素(catechin,C)、表儿茶素(epicatechin,EC)和表儿茶素没食子酸酯(epicatechin gallate,ECG)的含量在不同保鲜处理组中均出现了显著下降(p<0.05);表没食子儿茶素(epigallocatechin,EGC)、没食子儿茶素(gallocatechin,GC)和表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)的含量在5~8℃或10~13℃处理组中无显著性变化。此外,通过基于可溶糖、游离氨基酸、C、EC、ECG、GC、EGC和EGCG的主成分分析发现,在处理36 h后4组低温样品均能与常温样品进行区分,且较常温样品更接近0 h对照样品。综上所述,10~13℃处理能对茶青起到较好的保鲜作用。

Changes in Contents of Quality Related Components of Tea Leaves under Different Preservation

In this work,the plucked tea leaves were preserved at different temperatures,including a range of refrigeration at 5~8℃,10~13℃,and 15~18℃,as well as a room temperature storage at 21~23℃,for 36 hours.Changes of quality-related components of tea leaves were investigated during the process of preservation through detecting biochemical indexes.The content of soluble sugar showed no significant changes in neither refrigeration nor room temperature sample groups after 36 hour treatment.The content of free amino acids maintained at the same level before and after 36 hour refrigeration at 10~13℃.The catechin(C),epicatechin(EC),and epicatechin gallate(ECG)decreased significantly in all preservation treatments(p<0.05).The contents of epigallocatechin(EGC),gallocatechin(GC),and epigallocatechin gallate(EGCG)demonstrated no significant variation after 36 hour refrigeration at neither 5~8℃nor 10~13℃.The result of principle component analysis(PCA)suggested all samples of four refrigeration treatments were separated from the room temperature ones on the basis of soluble sugar,free amino acids,C,EC,EGC,GC,EGC,and EGCG.The refrigerated samples also clustered closer to the fresh leaves than the ones of room temperature case.In conclusion,10~13℃treatment could be a better choice to store plucked tea leaves.