Study On Tea Quality Of Different Varieties Processing Based On Liubao Tea Technology

Liubao tea is a black tea with a history of over 1500 years and is a famous tea in Guangxi.Its dry tea has a dark brown color,a strong and bright red soup color,a mellow and refreshing taste,and a mellow aroma.It has unique quality characteristics of red,strong,aged,and mellow.The quality formation of Liubao tea is closely related to the variety of raw materials,and developing fresh leaf raw material bases and determining suitable tea tree varieties for producing high-quality Liubao tea are currently urgent issues that need to be addressed.This study selected four different varieties of Cangwu group roasted Qingmao tea(Group C),Longji group roasted Qingmao tea(Group L),Yunkang No.10 roasted Qingmao tea(Group Y),and Heilongtan group roasted Qingmao tea(Group H)for fermentation based on the Liubao tea process.The raw materials of each group were taken,and the samples were turned over and piled up at each stage for sensory evaluation and biochemical composition detection.The raw materials of each group were taken,and the third turn was performed Fifth flip and stack samples for comparative study of volatile aroma components,to explore the quality characteristics and differences of different varieties of tea processed using Liubao tea technology.The specific conclusions are as follows:Using sensory evaluation methods,sensory evaluation was conducted on different stages of different varieties C(Cangwu population species)group,L(Longji species)group,Y(Yunkang No.10)group,and H(Heilongtan population species)group.After fermentation in a pile,the appearance of each group changes from yellow green to green brown,and finally turns into black brown.The aroma changes from chestnut and honey to frankincense,and cellar aroma finally turns into Chen Xiang and Yao Xiang.The soup color changes from yellow green bright to orange red,and finally turns into red bright.The taste changes from sweet and mellow to mellow,and the color of the leaf base changes from yellow green soft and bright to yellow brown,and finally turns into brown.Having the quality characteristics of "red,thick,aged,and mellow".C6 has a rich and pure aroma,with zongzi leaves and a hint of betel nut fragrance.The taste is mellow and sweet,returning to sweetness;L6 fragrance with a medicinal aroma,less pure taste,sweet and mellow,smooth,and refreshing feeling;Y6 has a medicinal aroma and a strong taste;H6 has a fragrant,aged and medicinal aroma,with a sweet and mellow taste that returns to sweetness and smoothness.Among them,the comprehensive sensory evaluation scores of tea samples made from Yunnan variety Yunkang No.10 and Heilongtan population variety were superior to Guangxi variety Longji and Cangwu population varieties.After the fermentation of the pile,compared with the raw materials,the tea polyphenol content,catechin content,amino acid content,and soluble sugar content in each group’s pile samples decreased,while the caffeine content increased and decreased,with little fluctuation.The content of catechins and soluble sugars in C6 is higher than that in other groups,the content of caffeine and tea polyphenols in L6 is higher than that in other groups,and the content of amino acids in Y6 is higher than that in other groups.Using GC-MS technology to analyze the changes in the content of aroma components in 16 tea samples of different varieties and stages before and after Wodui tea,a total of 121 volatile components were selected,including alcohols(28 types),esters(20 types),ketones(12 types),aldehydes(13 types),hydrocarbons(37 types),heterooxygens(10 types),and other compounds(4 types).There are significant differences in the aroma characteristics and composition of different raw materials,The main volatile components of C6 are hydrocarbons(47.36%),including cedar dilute and 1-methylnaphthalene;The main volatile component of L6 is heterocyclic compounds(29.91%),including 2,2,6-trimethyl-6-vinyltetrahydro-2H-furan-3-ol;The main volatile components of Y6 are ketones(24.93%),including geranyl acetone;The main volatile components of H6 are alcohols(21.14%),which contain lauryl alcohol and linalool.Calculate the OAV values of 21 substances through OAV.There are 14 types of aroma compounds with an OAV value of ≥ 1 in C,12 in L,11 in Y,and 11 in H.Among the four samples,significant contributions are made by aromatic compounds such as benzyl alcohol,decanal,and nonanal α-Violone β-Vionone,1-octen-3-ol,Cedarol,Linalool,Trans Linalool Oxides(furan type).Among them,the typical violet flower fragrance and sweet fragrance β-In this study,ionone has a high OAV and exhibits odor characteristics,making it one of the important contributing components to the "Chen Xiang" in the sample;Cedarol,with a light cedar wood aroma,is the main aroma component in Liubao tea.Nonal is a contributing component of Liubao tea wood fragrance and herbal fragrance.α-Ziluo ketone also has similar properties β-The floral characteristics of ionone,but its woody aroma is more prominent.Decanal has obvious odor characteristics of aldehyde compounds,as well as fat and citrus odors.Sweet,floral,and orange scented linalool,as well as mushroom like odors,and green scented 1-octen-3-ol are common and important volatile components.Thus,the varieties of tea trees used to produce Liubao tea in Guangxi were screened,and the Yunnan big leaf variety suitable for producing Pu’er tea was used as a control,in order to provide a reference basis for further selecting suitable raw materials for Liubao tea,and to provide high-quality raw materials for improving the quality and efficiency of Liubao tea and industrial production.