微波杀青对茶在制品物理特性影响的初探

以一芽一叶的福鼎大白茶鲜叶为原料,设定6个微波杀青的时间梯度(0、30、60、90、120、150 s),按时间点取样,测定在制品的含水率、容重、色差Lab值、长度、宽度等,研究微波杀青时间对茶在制品物理特性的影响。结果表明,随着微波杀青的进行,在制品的含水率在前90 s匀速缓慢下降,而后急速下降,容重在微波30 s后显著下降;茶在制品的平均相对长度差、相对宽度差和面积差呈现先降后升的趋势,在微波60~90 s时相对最小;在制品色差L值、|a|值、b值随着微波杀青的进行,呈先升后降的趋势,微波前90 s均较鲜叶有显著提升,而后显著下降。相关性分析表明,微波杀青时间和含水率均对L值、|a|值、b值、相对长度差等呈显著影响,总体上看以微波杀青60~90 s最有利于获得较优的外形属性。

Effect of Microwave Fixation on the Physical Characteristics of Tea Fresh Leaves

One leaf and a bud shoot was utilized as material and six microwave fixation time (0, 30, 60, 90, 120, 150 s) were setted to study the time course of microwave fixation effects on physical characteristics of tea products. Samples at different time points were taken to determine the value of water content, bulk destiny, Lab color values, length and width. The results showed that with the time course of microwave fixation, moisture content of tea fresh leaves decreased slightly first and then rapidly with the turning point at 90 s. Bulk destiny significantly reduced in first 30 s. Relative length, width and area differences were also decreased first and then increased, with the bottom at 60-90 s. L, a and b color values showed the opposite trends with the peaks at 90 s. The correlation analysis showed that L value, |a| value, b value and relative length difference were significantly affected by the microwave fixation time and water content. Overall, the best shape properties were obtained by microwave fixation for 60-90 s.