Study On Characteristic Substances And Key Aroma Components Of Pu-erh Tea (Ripe Tea)

Tea aroma quality is one of the essential factors that determine the quality of tea,which plays a significant role in tea flavor,grade evaluation,and public consumption orientation.Yunnan Pu-erh tea(ripe tea)enjoys a good reputation overseas for its unique aging fragrance quality.However,the characteristics of aging fragrance quality and its material basis are still unclear.Exploring the composition and formation of aging fragrance quality is conducive to further improving the quality of Pu-erh tea(ripe tea).In this paper,sensory evaluation combined with aroma component analysis and multivariate statistical analysis was used to study the aroma quality characteristics and substance composition of Pu-erh tea(ripe tea)made from raw materials of different fermentation stages and different origins and to discuss the effects of processing technology and storage time on the formation of aroma quality.The main research conclusions are as follows:1.Sensory analysis of tea samples at different fermentation stages found that: under the same fermentation conditions,different producing areas presented different aroma characteristics at the same stage,but the aroma quality of the final product was similar,showing the characteristics of aging aroma as the main aroma,supplemented by wood aroma,medicinal aroma,and floral aroma.2.HS-SPME-GC-MS combined with sensory evaluation and PCA analysis of aroma components of Pu-erh tea(ripe tea)in different years,and the key aroma components were initially screened out to be seven classes of alpha substances,including terpineol,β-violone,phytosterone,n-hexal,1,2,3-methoxybenzene,1,1,6 trimethyl-1,2 dihydronaphthalene.3.The aroma of selected tea samples was evaluated from the aspects of pure difference,strength,height,and durability.Moreover,on this basis,key aroma recombination was carried out.The results showed that methoxybenzenes were the main constituent substances of the aging aroma type,which had a stale,musty,and stale flavor.Ketones,alkenes,and esters as auxiliary substances could better enrich the aroma level of Pu-erh tea(ripe tea).However,methoxy-benzenes play a leading role in the aroma characteristics of Pu-erh tea(ripe tea):(1)determine the aroma type of Pu-erh tea(ripe tea)(mainly aging aroma type);(2)determine the durability and intensity of Pu-erh tea(ripe tea)aroma.4.Correlation Analysis is used to analyze the detected aroma substances.Among them,36 groups of key aroma substances interact with other substances,focusing on methoxybenzenes and ketones.