不同杀青方法制备桑叶茶的品质测试分析

A Quality Test and Analysis to Mulberry Leaf Tea Prepared by Different Fixation Methods

杀青是桑叶茶形状和品质形成的关键工序。将采摘的新鲜桑叶采用微波加热、蒸气加热和滚筒加热的方法进行杀青处理,测试不同杀青方法加工后成品桑叶茶的感官品质及营养保健品质。结果表明,微波杀青加工桑叶茶的外形色泽、汤色、叶底等感官品质较好,总浸出率、总黄酮含量和游离氨基酸含量等各项指标均高于其它2种杀青方法加工的桑叶茶,且对水浸出率、可溶性糖含量以及总多酚含量3项指标的影响达到显著水平,但香气和滋味欠佳。综合各项测试结果认为,微波杀青能较好保持桑叶茶的营养保健品质和感官品质,可考虑优化微波杀青工艺参数改善桑叶茶的香气和滋味。

Fixing is the key process to ensure good appearance and quality of mulberry leaf tea product.The present study used microwave heating,steam heating and rolling press heating methods to fix freshly picked mulberry leaves and compared the quality of mulberry leaf tea products prepared from different fixation methods through sensory organ assessment and nutritional component analysis.The results showed that mulberry leaf tea prepared by microwave heating had good appearance,good tea liquid color,good infused leaf color and other favorable sensory quality.Its total infusion rate,total flavonoid content,free amino acid content and other various indexes were higher than those of the mulberry leaf tea prepared by the other two fixation methods.Nevertheless,its difference reached significant level on three indexes namely water infusion rate,soluble sugar and total polyphenol contents.However,its fragrance and taste was not of the mostly favored.Taken together,microwave fixation could preserve nutritional components and sensory quality well and further experiments are expected to optimize microwave fixation process for improving the fragrance and taste of mulberry leaf tea product.