Study On The Characteristic Aroma Vomponents Of Zijuan Tea Based On HS-SPME-GC-MS Technique

With the advent of the era of health,people are paying more and more attention to the health benefits of food,and tea is one of the top three beverages in the world deeply loved by consumers.At present,little research has been conducted on its characteristic aroma components.Therefore,this paper systematically conducted a study on the characteristic aroma components of Zijuan tea based on HS-SPME-GC-MS technology.By using the multi-factor sensory evaluation method in food flavor science,we established the correspondence between sensory quality factors and volatile compounds of Zijuan tea aroma,interpreted the characteristics of Zijuan tea presentation by correlation analysis,and constructed its flavor wheel and aroma profile map.The aim of this study is to enrich the flavor chemistry of Zijuan tea,improve the sensory evaluation of tea,construct an aroma profile diagram to visualize its representation,and explore its volatile components to analyze its characteristic aroma components.The main findings of this paper are as follows:(1)Zijuan white tea from Kunming area has the quality characteristics of continuous buds and leaves in appearance and still uniform;Aroma of strong floral and fruit aroma and pungent aroma;Soup color is yellow and bright;Taste is pure,mellow and sweet;Leaf bottom is indigo,soft and bright.Zijuan black tea has the quality characteristics of tight and even appearance;Rich aroma of flowers and fruits with sweet and spicy aroma;Red color;Sweet and mellow sweet taste;Indigo leaf bottom.The overall scores of Zijuan white tea and Zijuan black tea in Menghai area were lower than those in Kunming area.(2)As the withering of Zijuan white tea continued,its floral and fruit aroma became more intense,eventually forming the quality characteristics of strong floral and fruit aroma and pungent aroma.The analysis of the changes of volatile compounds at different stages of the withering process showed that the total amount of volatile compounds increased gradually as the processing progressed.(3)As the processing of Zijuan black tea continued,its floral and fruity aroma became more intense,and caramel and sweet aroma appeared in the late fermentation stage,and the unique spicy aroma of Zijuan also became more obvious,finally forming the quality characteristics of strong floral and fruity aroma with sweet aroma and obvious spicy aroma.The analysis of the changes of volatile compounds at different processing stages showed that the total amount of volatile compounds showed a gradual increase as the processing progressed,with the proportion of alcohols increasing and being the main volatile compounds,while the rest of the compounds showed a decreasing trend.(4)HS-SPME-GC-MS and OAV techniques were used to analyze the volatile components of Zijuan white tea.The results showed that a total of 20 key aroma active substances were screened,among which linalool and methyl salicylate,which presented floral and fruity aromas,dominated the formation of floral and fruity aromas in its samples;benzaldehyde and laurylenes,which had pungent aromas,and2-methylbutyraldehyde,which had almond flavor,constituted its pungent and strong characteristics.Meanwhile,combined with the results of OPLS-DA analysis2-methylbutyraldehyde(almond)and 2-heptanol(fruity)were considered as the key compounds causing the difference in aroma of Zijuan white tea from different origins.(5)HS-SPME-GC-MS and OAV techniques were used to analyze the volatile components of Zijuan black tea signatures.The results showed that a total of 18 key aroma active substances were screened,and the substances with floral and fruit aroma,linalool,methyl salicylate,2-heptanol,n-hexanal,nonanal,isoamyl aldehyde and geraniol together played an important contribution to its quality characteristics of strong floral and fruit aroma with sweet aroma,and benzaldehyde played an important contribution to its obvious characteristics of spicy aroma.Meanwhile,combined with the results of OPLS-DA analysis methyl salicylate(floral aroma),2-heptanol(fruity aroma),1-octen-3-ol(tender aroma),nonanal(tender aroma,fruity aroma),leaf alcohol ester caproate(tender aroma,fruity aroma),nerolidol(floral aroma),damascenone(floral aroma)were considered as the key compounds causing the difference in aroma of Zijuan black tea from different origins.(6)Nine VCs,namely linalool,methyl salicylate,β-viologenone,(+)-limonene,n-octanal,benzaldehyde,phenylacetaldehyde,2-heptanol,and 1-octan-3-ol,had important effects on the flavor formation of Zijuan tea.Octanal,benzaldehyde,2-heptanol,1-octen-3-ol,and phenylacetaldehyde played a key role in the formation of floral aroma of Zijuan tea;octanal,benzaldehyde,2-heptanol,1-octen-3-ol,phenylacetaldehyde,and methyl salicylate played a key role in the formation of fruit aroma of Zijuan tea;octanal,benzaldehyde,1-octen-3-ol,and phenylacetaldehyde affected the formation of tender aroma of Zijuan tea;benzaldehyde,1-octen-3-ol(+)-Limonene plays a key role in the formation of fresh aroma of Zijuan tea.