光质对红茶萎凋叶蛋白酶和淀粉酶活性及相关成分的影响

Effect of Light-waves Bands on Protease and Amylase Activity and Relative Components in Black Tea Withered Leaves

【目的】萎凋是红茶加工的第一步关键工序,光质萎凋是提升红茶萎凋品质的重要方法。【方法】以福鼎大白茶鲜叶为原料,以室内自然萎凋为对照,分析了红茶萎凋叶的蛋白酶、淀粉酶活性及相关生化成分在黄光(585 nm)、蓝光(460 nm)萎凋过程中的变化规律。【结果】在萎凋过程中,各萎凋组的蛋白酶、总淀粉酶和β-淀粉酶活性,以及游离氨基酸含量均呈升-降-升趋势,黄光组蛋白酶活性高于蓝光组与对照组;萎凋至4 h,黄光组的蛋白酶活性、对照组的总淀粉酶活性和β-淀粉酶活性、蓝光组的α-淀粉酶活性均最高,分别比茶鲜叶升高7.4倍、2.1倍、3.9倍、11.5%;萎凋至12 h,黄光组的蛋白质含量最低,降低63.9%,游离氨基酸含量最高,升高53.3%,对照组总淀粉含量最低,降幅29.6%,蓝光组的可溶性糖含量最高,升高15.7%。相关性分析表明,黄光组的蛋白酶活性与蛋白质含量呈负相关,与游离氨基酸呈正相关,而蛋白质含量与游离氨基酸含量呈较大负相关,系数为-0.586;α-淀粉酶活性与可溶性糖含量、总淀粉酶活性与β-淀粉酶活性均存极显著正相关,系数分别为0.932、0.989。【结论】黄光萎凋能显著提高萎凋叶蛋白酶活性和游离氨基酸含量,降低蛋白质含量;蓝光萎凋和室内自然萎凋则可提高萎凋叶淀粉酶活性和可溶性糖含量,降低总淀粉含量。

【Objective】Withering is the first essential process of black tea processing,and light withering is an important way to promote the quality of withered tea leaves.【Method】By using of tea cultivar‘Fuding-dabaicha’(Camellia sinensis cv.‘Fuding-dabaicha’)as fresh tea leaves material,taking the indoor natural withering as control,the variation of protease and amylase activity and relative biochemical components of black tea withered leaves under yellow light(585 nm)and blue light(460 nm)irradiation were analyzed.【Result】The rerults showed that there was a rising-decreasing-rising trend of protease,total amylse,β-amylse activity and free amino acid content included in all withered group tea leaves,otherwise,yellow group presented higher protease activity than that of blue and control group.After 4 hours withering,the protease activity of yellow group reached the highest level which was 7.4 times higher than that of fresh tea leaves,the total amylse andβ-amylse activity in control group appeared the highest peak which improving 2.1 and 3.9 times,while theα-amylse activity in blue group achieved the peak with 11.5%increasing amplitude.After 12 hours withering,yellow group had the lowest protein content which decreased 63.9%,and had the highest level of free amino acid content with 53.3%increasing extend.Meanwhile,there was a lowest level of total starch in control group and a highest level of soluble sugar in blue group,which decreased 29.6%and increased 15.7%respectively.Correlation analysis showed that the relationship between protease activity and protein content in yellow group was negative,but with a positive relationship between that of free amino acid content.There was a greater negative correlation coefficient between the content of protein and free amino acid which was-0.586,high significantly positive correlation betweenα-amylse activity and soluble sugar content with coefficient of 0.932,and the relationship between the activity of total amylse andβ-amylse was also very significantly positive with coefficient of 0.989.【Conclusion】The protease activity and free amino acid content would be increased and the protein content would be decreased under yellow light withering,while the total amylse activity and soluble sugar content would be increased and the total starch content would be decreased both under blue light and indoor natural withering.