绿茶加工中主要脂溶性色素变化及其对茶叶色泽品质的影响  

Variation of main lipophilic pigments and its influence on color quality duringthe process of green tea

作　　者：舒娜 汪蓓 欧阳珂 孟庆[1] 童华荣[1] SHU Na;WANG Bei;OUYANG Ke;MENG Qing;TONG Huarong(College of Food Science,Southwest University,Chongqing 400715,China)

机构地区：[1]西南大学食品科学学院,重庆400715

出　　处：《食品与发酵工业》2021年第10期170-177,共8页Food and Fermentation Industries

基　　金：重庆市现代山地特色高效农业茶叶产业技术体系(2019-6;2020-7)。

摘　　要：为研究脂溶性色素在绿茶加工中的变化规律及其与干茶色泽的内在联系,该文通过高效液相色谱及色差仪对绿茶加工中在制品的脂溶性色素及色度值进行测定,采用偏最小二乘回归法(partial least squares regression,PLSR)分析脂溶性色素组分和色差值的相关性。结果显示,在绿茶加工过程中,在制品的叶绿素种类在杀青后显著增加,类胡萝卜素种类在提香过程中逐渐减少。叶绿素及类胡萝卜素总量在加工中均呈下降趋势,经杀青和干燥处理后,在制品的叶绿素a、叶绿素b及类胡萝卜素含量显著降低,脱镁叶绿素含量显著增加,L^(*)和b^(*)显著下降,a^(*)显著上升,在制品色泽发生明显转变。脂溶性色素在提香工序中进一步降解损失,在制品色泽逐渐变暗。PLSR分析结果表明,影响在制品L^(^(*))、a^(*)和b^(*)的主要色素组分分别为15、14和15种。其中叶绿素a和叶绿素b与L^(*)呈显著正相关,与a^(*)呈显著负相关。脱镁叶绿素与L^(*)呈显著负相关,与a^(*)呈显著正相关。在绿茶加工中减少热处理对叶绿素a和叶绿素b的破坏有利于提升干茶色泽品质。High-performance liquid chromatography(HPLC)and colorimeter were used to study the variation of main lipophilic pigments and the changes of color during the green tea manufactory process.Meanwhile,partial least squares regression(PLSR)was performed on the connection between the pigments and color quality of green tea.The results showed that the numbers of chlorophyll species increased obviously during the pan-fire period,while carotenoid species were decreased during baking.Furthermore,the total content of chlorophylls and carotenoids decreased during the green tea manufactory process.The main steps,in which chlorophyll a,chlorophyll b and carotenoids decomposed,pheophytins formed greatly,a^(*)rose significantly,L^(*)and b^(*)decreased significantly,were pan-fire and first drying.The content of lipophilic pigments decreased continuously and the color became dark gradually during baking.Analysis of PLSR indicated that there were 15,14 and 15 key lipophilic pigments that affected L^(*),a^(*)and b^(*),respectively.The contents of chlorophyll a and chlorophyll b exhibited a significant positive correlation with L^(*),but had a significant negative correlation with a^(*).Moreover,the contents of pheophytin had a significant negative correlation with L^(*),but a significant positive correlation with a^(*).Reducing the damage of heat treatment to chlorophyll a and chlorophyll b in green tea processing can improve the color quality of dry tea.

关 键 词：绿茶加工 叶绿素 类胡萝卜素 色度值 偏最小二乘法 

分 类 号：TS272.51[农业科学—茶叶生产加工]