不同温度和酸碱度下鲜绿茶汁叶绿素热降解的动力学规律  

Degradation Kinetics Law of Chlorophyll in Fresh Green Tea Juice Under Different Temperature and pH

作　　者：赵振军[1,2] 高静[1] 邹万志 黎星辉[2] 

机构地区：[1]长江大学园艺园林学院,湖北荆州434023 [2]南京农业大学园艺学院,江苏南京210095 [3]宜昌市滨江公园管理处,湖北宜昌443000

出　　处：《贵州农业科学》2014年第2期152-154,共3页Guizhou Agricultural Sciences

基　　金：湖北省教育厅科学技术研究项目"鲜绿茶汁的保鲜技术研究"(Q20121208)

摘　　要：为了减少鲜茶汁加工中叶绿素的损失,以经杀青后的茶鲜叶榨取的原汁为试材,采用控制温度、调节pH值促进鲜绿茶汁叶绿素降解的途径,探讨鲜绿茶汁叶绿素的降解动力学。结果表明:鲜绿茶汁的叶绿素a和叶绿素b的热降解符合一级反应动力学规律,在pH值不变的情况下,鲜绿茶汁中叶绿素a和叶绿素b热降解反应速率常数随温度升高而降低,半衰期缩短。随pH值增加,叶绿素a的活化能变化范围为(27.80±0.29)^(57.31±0.48)kJ/mol,叶绿素b的活化能(Ea)变化范围为(42.95±0.79)^(56.51±0.43)kJ/mol。鲜绿茶汁加工中适量提高pH值与降低温度可减少叶绿素的损失。Degradation kinetics of chlorophyll in fresh green tea juice was studied for purpose of reducing chlorophyll loss in fresh tea juice processing. The method was adopted to facilitate the chlorophyll degradation by controlling temperature and regulating pH value.The results showed that the breakdown of chlorophyll a and chlorophyll b belonged to a first-grade reaction.With the increase of temperature,the rate constant and half-life value of chlorophyll a and chlorophyll b decreased under the condition of same pH value.The activation energies ranged in （27.80＆#177;0.29）^（57.31＆#177;0.48）kJ/mol and （42.95＆#177;0.79）~ （56.51 ＆#177; 0.43）kJ/mol for chlorophyll a and chlorophyll b with the rise of pH value, respectively.Properly increasing pH value or decreasing temperature of fresh green tea juice was benefit for preserving chlorophylls during the process of fresh green tea juice.

关 键 词：鲜绿茶汁 叶绿素 降解动力学 

分 类 号：S517.1[农业科学—作物学]