萎凋时间对丹霞8号主要生化成分和挥发性成分的影响

Effect of withering time on biochemical components and volatile of tea leaves from Danxia 8

以丹霞8号为试验材料,比较不同萎凋时间茶叶中生化成分和挥发性成分,探明其变化规律。结果表明:茶多酚含量在0~23h显著增加,23~32h显著降低。0~16h游离氨基酸含量显著增加,茶氨酸则显著降低;16~50h游离氨基酸和茶氨酸均显著降低。0~50h咖啡碱含量显著增加;可可碱显著降低;叶绿素a差异不显著。叶绿素b和类胡萝卜素含量在5~28h显著降低;28~50h显著增加。萜烯是5~32h萎凋叶主体挥发性成分,萜醇是0h和50h萎凋叶主体挥发性成分。主成分分析表明,0~50h萎凋叶的生化成分特征和香气轮廓呈规律变化,生化特征可分为0~16,23~28,32~50h3个阶段;香气轮廓分为0~9,16~23,26~32,50h4个阶段。16h和23h是茶叶萎凋过程中生化成分特征和香气轮廓变化的共有时间点。

The comparative analysis was performed for the biochemical components,and volatile of tea leaves from Danxia 8 treated at different withering time.The regularity of biochemical characteristics and aroma profile were expected to find out by statistical methods.The results showed that tea polyphenols increased significantly from 0 hto 23 h,and then decreased significantly.The content of free amino acids increased significantly from 0 hto 16 h,while theanine decreased remarkably.The contents of free amino acids and theanine decreased significantly in the next time.At the whole withering process,caffeine content increased significantly,but theobromine decreased remarkably.Chlorophyll a content had not a significant change.The contents of chlorophyll b and carotenoids decreased significantly from 5 h to 28 h,followed by significant increase.Terpenes were identified as the main volatile of withered leaves from 5 hto 32 h.Terpenols were the main volatile at the time of 0 hand 50 h.Based on principal component analysis, biochemical characteristics and aroma profiles of withered leaves showed a regularity.The biochemical characteristics could be divided into three stages,including 0~16,23~28 and 32~50 h.The aroma profiles became into four stages,including 0~9,16~23,26~32 and 50 h.The time of 16 hand 23 hwere the mutual demarcation for biochemical characteristics and aroma profile during the withering process.