“发花”对白茶风味品质的影响研究

以白牡丹和寿眉为研究对象,通过感官审评得知"发花"能够赋予白茶新的风味,对寿眉风味品质的提升尤为显著。"发花"对白茶风味的影响主要体现在香气由鲜爽青涩转向陈香且青涩味消退,具有典型的菌花香。这表现在赋香物质中清鲜味的组分含量减少,而木香和陈香的组分含量提高。滋味从青涩、粗老向陈醇转变。这是由于白牡丹和寿眉在"发花"后呈涩味和收敛性的酯型儿茶素分别降低了2.3和0.69个百分点。茶黄素分别降低了33%和43%。白牡丹"发花"后滋味微苦可能是由于其咖啡碱含量显著升高。"发花"后白牡丹中必需氨基酸占非必需氨基酸的总量从36.10%上升到39.84%,寿眉必需氨基酸占非必需氨基酸的总量从42.16%上升到62.61%,因此"发花"可能存在提高中低档白茶营养价值的潜能。总体来说,寿眉在"发花"后的风味提升要大于白牡丹,这对提高中低档白茶的品质具有重大意义,是一个综合开发利用白茶资源的新思路。

Study on Effect of Fungal-fermentation Process on Flavor Quality in White Tea

Baimudan and Shoumei were utilized to study the effect of fungal-fermentation process on flavor quality. Sensory evaluation found new flavors in white tea after fermentation. The quality of Shoumei was improved significantly after fermentation. The aroma of white tea changed from clean and fresh to pure and mellow during fermentation, which was due to the decrease of fresh odorants and increase of aged fragrant. The taste changed from astringent and harsh to aged and soft, which was attributing to the decrease of esters-catechins by 2.3 and 0.69 percent respectively, and theaflavin by 33% and 43% respectively in Baimudan and Shoumei. The taste of fermented Baimudan was a little bitter because caffeine increased significantly. The ratio of essential amino acids to nonessential amino acids increased from 34.95% to 38.12% in Baimudan and 42.16% to 62.32% in Shoumei. Therefore, fungal fermentation could largely improve the value of low or middle-grade white tea. In summary, The impacts of fungal fermentation on quality of Shoumei were larger than that of Baimudan, which is of great significance to improve the quality of low grade white tea.