针形红茶精揉做形工艺参数优化

Optimization of Shaping Process Parameters for Needle-shaped Black Tea

【目的】探明精揉做形工艺对针形红茶品质的影响,为针形红茶加工提供理论依据。【方法】采用单因素试验分析投叶量、含水率、做形时间和做形温度对针形红茶感官品质得分的影响,并通过L_(9)(3^(4))正交试验设计优化精揉做形工艺参数。【结果】在其他处理条件固定的情况下,当茶坯含水率为30%时针形红茶的感官品质评分最高,为91.25分;当做形温度为100℃时针形红茶的感官品质评分最高,为91.65分;当做形时间为25 min时针形红茶的感官品质评分最高,为91.25分;当投叶量为3.0 kg/槽时针形红茶的感官品质评分最高,为91.40分;通过正交试验得出针形红茶精揉做形工艺最佳参数为投叶量2.8 kg/槽+含水率32%+做形时间30 min+做形温度100℃,此条件下针形红茶的感官品质评分最高,为92.75分。各因素对精揉做形品质影响程度依次为做形时间>含水率>做形温度>投叶量。【结论】精揉机做形针形红茶的最佳工艺流程及参数为茶青原料→萎凋(热风萎凋,时间4~6 h,萎凋后含水率56%左右)→揉捻(投叶量55 kg/桶,揉捻时间70 min,加压轻重轻)→发酵(温度30℃,湿度95%以上,时间2~3 h)→毛火(进口热风温度130℃,时间8 min)→精揉做形(投叶量2.8 kg/槽,茶坯含水率32%,做形温度100℃,做形时间30 min)→足火(80℃烘至足干)。

【Objective】The study aims to explore the influence of shaping technology on the quality of needle-shaped black tea and to provide the theoretical basis for processing needle-shaped black tea.【Method】Single factor experiment is used to analyze the effects of leaf amount,water content,shaping time and shaping temperature on the sensory quality score of needle-shaped black tea,and then L_(9)(3^(4))orthogonal test design is adopted to optimize the shaping process parameters.【Result】Under the constant situation of other treatment,the highest sensory score of needle-shaped black tea is 91.25 when the moisture content of tea is 30%;When the shaping temperature is 100℃,the highest sensory score is 91.65;When the shaping time is 25 min,the highest sensory score is 91.25;when the leaf amount is 3.0 kg/tan k,the highest sensory score is 91.40;Through the orthogonal test,the optimum shaping process parameters of needle-shaped black tea include 2.8 kg/tank leaf amount+32%moisture content+30 min shaping time+100℃shaping temperature.Under the optimum conditions,the sensory score of needle-shaped black tea is the highest of 92.75.The influence of each factor on the shaping quality follows shaping time>moisture content>shaping temperature and leaf amount.【Conclusion】The optimum process and parameters of shape-fixing machine shaping needle-shaped black tea include tea material→withering(withered by hot wind for 4~6 h,with moisture content of 56%or so after withering)→twisting(55 kg/tank leaf amount,twisting for 70 min,and pressurizing light,heavy and light)→fermenting(fermenting at 30℃for 2~3 h and the moisture content is above 95%)→primary firing(hot wind at 130℃for 8 min)→shaping(2.8 kg/tank leaf amount,32%water content,shaping at 100℃for 30 min)→final firing(80℃curing to dry)