碎茶吸湿特性研究

Research on the Hygroscopicity of Broken Tea

以云南大叶种CTC红碎茶、浙江小叶种蒸青绿碎茶为原料,经粉碎后依次过不同目数的筛网,获得不同细度的碎茶。碎茶经脱湿平衡后,在温度25℃,相对湿度为75%的环境下测定其吸湿增重随时间变化情况,获得吸湿时间曲线并进行拟合分析,同时对碎茶的吸湿特性及物理特性进行相关性分析,研究不同碎茶的吸湿特性。结果表明,红碎茶与绿碎茶的吸湿时间曲线均与一元三次方程Y=aX^(3)+bX^(2)+cX+d(a<0)拟合,30目细度的红碎茶和绿碎茶拟合度最好,R^(2)分别为0.949和0.984。相关性分析表明,在0.05水平,红碎茶平衡吸湿增重与细度存在显著负相关性;在0.01水平,绿碎茶的平衡脱水率与自由流动堆积密度、紧密堆积密度存在显著正相关性;与红碎茶不同的是,绿碎茶的平衡吸湿增重与细度、自由流动堆积密度、紧密堆积密度间均呈正相关性,且细度与平衡脱水率间存在显著正相关性。红碎茶与绿碎茶的吸湿差异性可能与其加工工艺有关。

CTC red tea of Yunnan large leaf species and steamed green tea of Zhejiang small leaf species were used as raw materials.After being crushed,the raw materials passed through screens of different mesh numbers successively,and different sizes of tea was obtained.After dehumidification balance,moisture absorption and weight gain of crushed tea were measured over time in an environment of 25℃and 75%relative humidity.The moisture absorption time curve was obtained and fitting analysis was carried out.Meanwhile,correlation analysis was conducted on the moisture absorption characteristics and physical characteristics of crushed tea to study the moisture absorption characteristics of different crushed tea.The results showed that the moisture absorption time curves of red and green crushed tea were fitted with the cubic equation Y=aX^(3)+bX^(2)+cX+d(a<0),and the 30 mesh fineness of red and green crushed tea had the best fitting degree,and R^(2) was 0.949 and 0.984 respectively.The correlation analysis showed that there was a significant negative correlation between the weight gain and fineness at the level of 0.05.At the level of 0.01,there was a significant positive correlation between the equilibrium dehydration rate of green tea and the free flow accumulation density and the compact accumulation density.Different from red tea,the balance moisture absorption and weight gain of green tea were positively correlated with fineness,free flow accumulation density and compact accumulation density,and there was a significant positive correlation between fineness and equilibrium dehydration rate.The difference of moisture absorption between green tea and red tea may be related to its processing technology.