揉捻过程中茶叶物理特性的变化规律

The Variation Law of Physical Properties of Tea in the Rolling Process

为研究揉捻过程中茶叶含水率、柔软性、弹塑性及孔隙率等物理特性的变化规律,以华农绿茶鲜叶为原料,经萎凋、杀青并回潮之后进行揉捻加工,分别采用103℃恒重法、质构仪法、仪器法对以上几个茶叶物理性质进行测定,分析它们的变化规律。结果表明,揉捻过程中茶叶的含水率与揉捻时间呈负相关,y赞=-0.032 7 x+46.421,决定系数r2=0.959;揉捻过程中茶叶的弹性与揉捻时间基本呈线性正相关,y赞=0.134 2 x+12.92,决定系数r2=0.956;而柔软性和塑性都是先增加后减小,25 min左右时最小,若着重考虑茶叶外形,则茶叶成形的最佳揉捻时间是25 min左右;揉捻过程中茶叶的孔隙率随揉捻时间呈开口向上的抛物线趋势,两者的关系可以用y赞=0.000 6 x3-0.021 5 x2-0.057 x+69.86来表示,决定系数r2=0.964。

To investigate the variation law of tea moisture content, flexibility, elasticity, plasticity and porosity in rolling prosess, using Huanong green tea leaf as raw material, the above physical properties were determined by 103° constant weight method, texture analyzer methed and apparatus method. The results showed that the moisture content of tea was nega- tively correlated with the rolling time in rolling process, y=-0.032 7 x＋46.421, r2=0.959. The tea elasticity and rolling time showed a positive linear correlation, y=0.134 2x＋12.92, r2=0.956. The tea flexibility and plasticity were firstly increased and then decreased in the rolling time; and the best rolling time for tea forming was about 25 min. The tea porosity and rolling time presented a parabolic trend, y=0.000 6 x3-0.021 5 x2-0.057 x＋69.86, rZ=-0.964.