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研究中国绿茶传统加工过程不同工艺阶段茶汤总酚、总黄酮、抗坏血酸含量和抗氧化能力的变化。加工成品的总酚含量从鲜叶的119.91mg/g(以干质量计)下降到100.33mg/g,总黄酮含量也有相似的变化趋势,从2.90mg/g下降到2.04mg/g,且这两种成分的降低主要发生在“回潮”阶段。此外,加工过程中茶汤抗坏血酸含量也逐渐下降(从4.17mg/g降至2.95mg/g)。尽管经过剧烈的加工,鲜叶总抗氧化能力(TEAC)仅出现轻微降低,TEAC从(524.94±18.68)μmol/g降至成品中的(487.03±17.97)μmol/g,但总酚和总黄酮与TEAC无线性关系(R2=0.19,R2=0.01),而DPPH自由基与总酚和总黄酮有较好的线性关系(R2=0.77,R2=0.56)。此外,加工过程中茶叶抗自动氧化能力增强(抑制率从52.45%增加至78.12%)。表明中国绿茶传统加工过程导致成品茶汤主要抗氧化物质含量的减少,但仅导致其抗氧化能力的轻微改变。
To study the changes of total phenolics, flavonoids, ascorbic acid content and antioxidant capacity in tea during different stages of green tea traditional processing. The total phenolic content of processed products decreased from 119.91mg / g (dry weight) of fresh leaves to 100.33mg / g, and the content of total flavonoids also showed a similar trend, from 2.90mg / g to 2.04mg / g, The reduction of both components occurs mainly in the stage of “resurgence”. In addition, the ascorbic acid content of the tea leaves decreased gradually during processing (from 4.17 mg / g to 2.95 mg / g). Although only a slight decrease in total antioxidant capacity (TEAC) and TEAC decreased from (524.94 ± 18.68) μmol / g to (487.03 ± 17.97) μmol / g in the finished product after severe processing, the total phenolic and total flavonoids (R2 = 0.19, R2 = 0.01), while the DPPH free radical has a good linear relationship with total phenolics and total flavonoids (R2 = 0.77, R2 = 0.56). In addition, the ability of tea to resist auto-oxidation during processing was enhanced (the inhibition rate increased from 52.45% to 78.12%). The results showed that the traditional processing of Chinese green tea led to the decrease of the content of the main antioxidants in the finished tea, but only led to a slight change of its antioxidant capacity.