Difference Quality Characteristics of Xihu Longjing Tea with Different Processing Technology

In order to clarify the differences of quality characteristics of Xihu Longjing tea with different processing technologies, four processing methods were used to process the Xihu Longjing tea, including the method of processing tea with machines in all processes, the method of handmade processing after one fixation by machine, the method of handmade processing after two fixation by machine, and the method of handmade tea for all processes. The sensory quality and the content of physical and chemical components were compared and analyzed, and the relationship between color difference and soup color was analyzed. The results showed that the shape of the tea made by handmade processing after one fixation by machine and handcraft processing after two fixation by machine was better than that of handmade tea for all processes. The taste and aroma of the Xihu Longjing tea by the handmade processing after one fixation by machine was similar to that of the handmade tea for all processes, and it was better than that of the processing tea with machines in all processes. There were no significant differences in polyphenol content, caffeine content, free amino acid content and L value (P>0.05) among four processing methods, but significant differences in a value and b value (P<0.05). The method of handmade processing after one fixation by machine was conducive to the retention of key flavor chemicals such as EGCG, GCG, glutamine and theanine in Xihu Longjing tea. The taste and aroma quality of the Xihu Longjing tea was significantly improved by the innovative technology of handmade processing after one fixation by machine, which was equivalent to the tea by handmade tea for all processes. It can provide technical support and theoretical basis for the quality improvement of Xihu Longjing tea.