Study On The Dynamic Change Of Fresh Leaf Yield And Quality Of Yanshan Black Tea In Wanzhou

This study taken the fresh leaves of "Chuan leaflet" tea as the research object which collected from the organic tea garden of Wanzhou Yanshan Quanshui village,in order to establish a theoretical basis for the planting and the improvement of the quality of organic black tea,the yield and quality of organic black tea were monitored.The 100-bud weight,leaf length,leaf area,bud density and yield of fresh tea leaves were measured by general statistical method;the mineral elements(K,Na,Mg,Cu,Zn,Ca,Fe,Mn)were determined by ICP-MS;Water content,ash content,water extract,free amino acid,tea polyphenols,caffeine and soluble sugar were determined by physical and chemical analysis;the method specified in GB/T 23776-2018 was used for sensory evaluation of black tea;various analytical methods were used to process the data.The results show that: 1.The hundred-bud weight,bud density,leaf length and area of fresh leaves showed a decreasing trend in general,and the yield of fresh leaves from summer to winter also showed an extremely significant decreasing trend.The contents of water,free amino acids,tea polyphenols,caffeine,water extract and mineral elements(K,Na,Cu,Zn)showed a decreasing trend,while the contents of soluble sugar,ash and mineral elements(Ca,Mg,Fe,Mn)showed an increasing trend with the decreasing of fresh leaf tenderness.The contents of water,ash,tea polyphenols,caffeine,water extract and soluble sugar of fresh leaves had significant differences among different months,but the free amino acids had no significant differences.There was a positive correlation between free amino acids,tea polyphenols,caffeine and water in fresh leaves,and a negative correlation between ash and water extract.The characteristic chemical components of fresh leaves are free amino acids,tea polyphenols,caffeine and water,Therefore,it can be concluded that the quality of fresh tea leaves in Chawang area is better than Underforest and Tingfengting area.The clustering of chemical components in fresh leaves was consistent with the seasonal rule of summer,autumn and winter,and had certain seasonal characteristics,which could provide reference for the quality judgment of fresh leaves.Content of mineral elements content in fresh tea leaves is higher,the order of content size was the size of K,Ca,Mg,Na,Mn,Fe,Cu and Zn.The quality components and mineral elements in fresh tea leaves promote and inhibit each other.The order of quality of fresh tea leaves is summer,autumn and winter.3.The order of sensory evaluation of spring,summer and autumn black tea is spring tea,summer tea and autumn tea,that the contents of free amino acids,tea polyphenols,caffeine and water extract were significantly positively correlated with the sensory comprehensive quality of tea.The content of ash and soluble sugar was significantly negatively correlated with the sensory comprehensive quality of tea.There was no correlation between moisture and sensory quality of tea.In conclusion,from summer to winter,the quality and yield of fresh leaves of "Sichuan leaflet" tea decreased;there are synergistic and antagonistic effects between quality components and mineral elements in fresh tea leaves;selective absorption of mineral elements in fresh tea leaves which rich in mineral elements;the contents of other chemical components and mineral elements in fresh leaves of tea varied greatly in different months,but the content of free amino acids was relatively stable;The sensory evaluation quality of tea is closely related to the content of chemical components in fresh tea leaves.