高茶黄素速溶红茶的酶促氧化工艺优化及品质分析

为实现夏秋绿茶的高值化利用，本研究以夏秋绿茶为原料，开发一款高茶黄素速溶红茶。在单因素实验的基础上，通过响应面法优化酶促氧化工艺条件，最后对产品的感官评价、理化指标及香气组分进行了分析。结果表明，最优工艺为:酶添加量1/1000 (mL/mL)，pH4.90，反应温度50 ℃，反应时间44 min。在该工艺条件下，产品清香可口，汤色橙红透亮，茶黄素含量高达2.11%±0.04%，理化指标均达到相关标准要求。采用顶空固相微萃取(headspace solid-phase microextraction，HS-SPME)结合气质联用(gas chromatography-mass spectrometry，GC-MS)法，共检测出70种香气组分，包括醇类16种，酮类15种，醛类6种，酯类9种，酸类5种，酚类4种，碳氢类5种，其他10种。其中醇类相对含量占比最高，高达32.34%±0.14%，整体香气轮廓主要呈现青草香与花香。该研究结果为我国茶叶深加工的发展提供了一定的理论依据。

Optimization of Enzymatic Oxidation Process and Quality Analysis of High-theaflavins Instant Black Tea

In order to realize the high-value utilization of summer-autumn green tea, this study used summer-autumn green tea as the raw material to develop a high-theaflavins instant black tea. Based on single-factor experiments, the enzymatic oxidation process conditions were optimized by response surface methodology. Finally the sensory evaluation, physicochemical index and aroma component of the product were analyzed. The results showed that the optimal process was as follows: Enzyme addition amount of 1/1000 (mL/mL), pH of 4.90, reacted at 50 ℃ for 44 min. Under this process condition, the product obtained, which possessed a sweet fragrance and a bright orange-red liquor color, had theaflavin content as high as 2.11%±0.04%, and physicochemical indicators all met the relevant standard requirements. A total of 70 aroma components, including 16 alcohols, 15 ketones, 6 aldehydes, 9 esters, 5 acids, 4 phenols, 5 hydrocarbons and 10 others were detected by HS-SPME combined with GC-MS. The highest relative content of alcohols was 32.34%±0.14%, and the overall aroma profile was mainly grassy and floral. The results of this study have provided a theoretical basis for the development of deep processing of tea in China.