Study on Aroma Identification and Quality Characteristics of Fenghuang Dancong Tea with Different Aroma Types

In order to explore the differences of main biochemical components and aroma characteristics of different flavor types of Fenghuang Dancong tea, the electronic nose aroma detection technology, the determination of biochemical components of tea and sensory evaluation were used to compare 8 flavor types and 17 Fenghuang Dancong tea samples produced in Chaozhou, Guangdong province. The results showed that the response values of 8 scented Fenghuang Dancong tea soup method and leaf bottom method were significantly higher than that of dry tea method, and the contribution rates of sulfide and terpenes to the aroma were the highest, reaching 188.24 and 178.79, respectively. The principal component analysis (PCA) of tea soup method was more accurate and effective than dry tea method and leaf base method. Linear discriminant analysis (LDA) was better than PCA in discriminating aroma types of tea. Loading analysis showed that nitroxides, sulfides and terpenes, alcohols and aldehydes, organic sulfides and methyl groups had higher contribution rates to tea aroma. The contents of water extract, tea polyphenols, free amino acids and theanine in 17 tea samples were 36.54%~49.46%, 9.13%~14.87%, 1.32%~2.44% and 0.75%~4.45%, respectively. Theaflavin, thearubigins and theabrownin contents were 0.04%~0.09%, 1.02%~2.58% and 0.99%~2.28%, respectively. In the sensory evaluation of tea samples, the highest score was 93.1 for the almond-scented old fir duck excrement fragrance, and the lowest score was 81 for the ginger-scented organic Nanjiang. The aroma and quality characteristics of different aroma types of Fenghuang Dancong tea are affected by the age, strain, production season and processing technology of the tea tree. The combination of electronic nose aroma component detection technology and sensory evaluation is a more scientific and reasonable measure to study the aroma of tea.