云南大叶种晒青茶发花前后主要风味成分的变化研究

以云南大叶种晒青茶为原料,采用散茶轻压、紧压茶手筑和机压的方法进行自然发花,分别制成轻压晒青散茯、手筑晒青茯砖和机压晒青茯砖,通过感官审评和理化检测,对晒青茶发花前后的感官品质和主要风味成分的变化进行研究.结果表明,发话后3种晒青茶的苦涩味和收敛性均明显减弱,滋味向醇和转变,香气由清香变为陈香且具有独特的菌花香,汤色由...

Study on the Changes of Main Flavor Components of Yunnan Large Leaf Sun-dried Green Tea Before and After Fungal Fermentation

Yunnan large leaf sun-dried green tea was used as raw material to make light pressed sun-dried green loose Fu tea,hand pressed and machine pressed sun-dried green Fu brick teas by natural fungal fermentation method.Through sensory evaluation and physical and chemical detection,the changes of sensory quality and main flavor components of sun-dried green tea before and after fungal fermentation were studied.The results show that:the bitter and astringent taste of the three fungal fermented sun-dried green teas was obviously weakened,and changed to mellow.The aroma changed from refreshing to aging and had a unique fungus fragrance.The liquor color changed from bright yellow green to bright orange,and the color of dry tea and infused leaves were obviously deepened.The contents of tea polyphenols,catechins,free amino acids,total flavonoids,soluble sugar etc.of the three fungal fermented sun-dried green teas decreased to varying degrees,especially the ester catechin decreased significantly with the decreasing rates of 56.91%(P<0.01),31.80%(P<0.05)and 64.06%(P<0.01)respectively.The contents of caffeine and water extract increased slightly,while the contents of tea polysaccharide,gallic acid and anthocyanin increased significantly.The relative contents of linalool and its oxides with flower and wood aroma and methyl salicylate with medicinal aroma in the fungal fermented sun-dried green teas increased from 33.94%and 1.92%before fungal fermentation to 56.73%,57.62%,45.98%and 8.47%,8.53%and 7.56%respectively.While the relative contents of other alcohols and most ketones with flower and fruit aroma and aldehydes with refreshing and green grass aroma decreased significantly.Among them,the relative contents of 1,2,3-trimethoxybenzene and 1,2,4-trimethoxybenzene with aging aroma increased significantly from 1.51%and 0.56%before fungal fermentation to 5.87%and 3.75%respectively in machine pressed sun-dried green Fu brick tea.Therefore,the refreshing aroma of sun-dried green tea decreased after fungal fermentation,showing the characteristics of aging aroma,and more obvious aging aroma was identified in the machine pressed sun-dried green Fu brick tea.