夏秋红茶的再加工与冷泡茶制备研究

Reprocessing and cold-brewing tea preparation of summer-autumn black tea

目的探索利用夏秋红茶再加工制作冷泡茶的可行性和最佳工艺条件。方法利用纤维素酶处理夏秋红茶,通过单因素实验和正交实验筛选最佳酶解条件,测定处理前后红茶中主要化学成分和挥发性风味物质变化,并对其冷泡性能进行评价。结果优化获得了夏秋红茶再加工的工艺条件为:纤维素酶添加量为1.2 kU/g,料液比为5:8(g:mL),处理时间为24h,处理温度为25℃。纤维素酶加工后茶叶中的主要滋味物质和风味物质含量以及冷泡性能等品质指标均有所提高。冷泡茶汤中的可溶性总糖含量由4.33%升高至9.35%,水浸出物含量由26.64%升高至35.73%。在挥发性风味物质方面,加工后茶叶中苯甲醇(芳香、果香)、苯乙醇(玫瑰花香、蜜香)和水杨酸甲酯(清香、花香)等特征香气物质的相对含量升高。冷泡性能方面,加工后的红茶水浸出物冷泡溶出大幅增加和可溶性总糖则可完全冷泡溶出,产品适于冷泡饮用。结论本研究通过纤维素酶再加工提升夏秋红茶品质,制备冷泡茶,不仅能实现夏秋茶资源的充分利用,也为冷泡茶的生产提供了稳定的原料供应。

Objective To explore the feasibility and optimum process conditions of making cold-brewing tea from summer-autumn black tea.Methods Cellulase was used to treat summer-autumn black tea,and the enzymatic hydrolysis conditions to prepare cold-brewing tea were optimized by single factor test and orthogonal test.The main chemical composition and volatile flavor compounds of black tea were analyzed before and after treatment,and the cold-brewing properties was evaluated.Results The optimized processing conditions for cold-brewing tea manufacture by reprocessing of summer-autumn black tea were optimized as:Cellulase addition amoun was 1.2 kU/g,the material-liquid radio was 5:8(g:mL),the treated time was 24 h and the treatment temperature was 25℃.After cellulase processing,the content of main taste compounds,flavor compounds and the cold-brewing properties of tea were improved,the total soluble sugar content was increased from 4.33%to 9.35%,and the content of water-soluble increased from 26.64%to 35.73%,other main taste substance did not change significantly.In terms of volatile flavor substances,the relative content of some characteristic aroma substances increased,like benzyl alcohol(aromatic,fruity),phenylethyl alcohol(rose-like,honey),methyl salicylate(fresh,floral).As for cold-brewing properties of tea,the cold bubble dissolution of the processed red tea extract was greatly increased and the total soluble sugar could be completely dissolved in cold bubble,,which indicated that the reprocessed tea was suitable for cold-brewing.Conclusion This study improves the quality of summer-autumn black tea by using cellulases to prepare cold-brewing tea,which can not only reach the full utilization of summer-autumn black tea,also provide a stable material for cold-brewing tea manufacture.