| In recent years,the domestic new tea beverage industry has developed rapidly,and the industrial scale is also expanding,but the new tea drink is facing problems such as the lack of suitable special raw material tea.Oolong tea is a base tea commonly used in new tea drinks,due to the lack of research on the influence of different varieties of oolong tea with different roasting degrees,it is impossible to select oolong tea suitable for roasting temperature as the tea base and to make theoretical guidance in the taste needs of new tea drinks.Through the study of six varieties of northern Fujian oolong tea with different roasting degrees produced by Jian’ou City,this paper determines the main taste and aroma components,explores the influence of sensory quality and content components of tea base on the sensory quality of new tea drinks,and provides a certain theoretical basis for better screening oolong tea with suitable roasting temperature as tea base to correspond to the taste needs of new tea drinks.The results of the study are as follows:1.In this experiment,6 varieties of northern Fujian oolong tea samples were used as materials,different roasting treatments were carried out,and Oolong tea was processed into Oolong tea as light baking tea at130°C by the initial production process,and then baked at 120°C for 4 h to medium heat,medium baking tea was roasted at 135°C for 4 h into heavy baking tea,and the content of biochemical components of 6varieties of tea samples was analyzed by one-way ANOVA,and the changes of the main biochemical components of northern Fujian Oolong were analyzed by PLS-DA and HCA combined with sensory evaluation results.The results showed that with the increase of roasting degree,the contents of water extract,amino acids,caffeine and tea polyphenols in the six tea varieties tended to decrease,while the contents of thearubigin and theaflavin increased or decreased.Light baking and heavy baking are the roasting degree that can best distinguish the components of tea-like biochemical substances,the amino acids and caffeine content of light baking tea are significantly higher than that of medium baking and heavy baking,As the degree of roasting increases,the taste of the tea soup gradually becomes mellow and thick,and the value of VIP>1 has water extract,amino acids,caffeine,indicating that water extract,amino acids,caffeine are the key biochemical components that form the taste difference of Fujian Northern Oolong with different roasting degrees.By controlling the chemical components such as water extract,amino acids of Fujian Northern Oolong tea through the degree of roasting,the quality and flavor of the tea can be adjusted,so as to provide a suitable tea base for the new tea drink.2.HS-SPME-GC-MS was used to detect the aroma components of Qilan,Huangmeigui and Rougui treated with light baking and heavy baking,and the characteristic substances were analyzed by OAV combined with multivariate statistical analysis method.The analysis results showed that a total of 331 aroma components were detected in 6 tea samples,mainly aldehydes,terpenes,heterocyclic compounds and esters.Based on the analysis of OAV value and partial least squares discriminant,13 key volatiles were screened out in light baking Oolong tea and 14 key volatiles were screened out in heavy baking Oolong tea.The results of PLSR correlation analysis showed that the characteristic aroma components of light baking Rougui were phenylacetaldehyde,2,4-heptadienal,hexanal,benzaldehyde,2-phenylethanol,α-farnesene,nerolidol,linalool,indole,and hexyl caproate with flowery and fruity aroma.The characteristic aroma component of light baking Qilan is β-ionone with flowery aroma;Methylpyrazine and 2,5-dimethylpyrazine are the characteristic aroma components of light baking Huangmeigui.The characteristic aroma components of heavy baking Rougui are terpenes such as α-farnesene,linalool,nerolidol and esters such as hexyl caproate andmethyl salicylate with flowery and fruity aroma.2,5-Dimethylpyrazine,phenylacetaldehyde and benzaldehyde are the characteristic volatile substances of heavy baking Huangmeigui;The characteristic aroma components of heavy baking Qilan are 2,4-heptadienal,furfural and 5-methylfurfural with a roasted aroma.3.In order to further explore the relationship between the sensory quality of the new tea drink and the components contained in the base tea,18 tea samples were made into fruit tea and milk tea,and the QDA data were processed by ANOVA and radar chart,and analyzed by HS-SPME-GC-MS.The results showed that the tea base made of light baking tea was suitable for making fruit tea,with strong orange aroma and strong and lasting tea taste,while the tea base made of heavy baking tea was suitable for milk tea,which showed obvious tea aroma,proper coordination with milk taste,and pure aroma.Among them,fruit tea made from light baking Rougui and milk tea made from heavy baking Rougui had the highest sensory evaluation scores.Based on the sensory evaluation results of tea drinking,the aroma components of light baking and heavy baking Rougui were determined,and the common aroma components mainly included alcohols,aldehydes,esters and heterocyclic compounds.The varieties suitable as a base tea for new tea drinks are Rougui with high content of terpenes and esters with flowery aroma and fruity aroma in volatile substances;Among them,Rougui suitable for making fruit tea is still heavy and mellow,flowery aroma and fruity aroma,the water extract in the biochemical components,the amino acids,caffeine content and the aroma components are floral and fruity indole,3,7-dimethyl-1,5,7-octane-3-ol,phenylacetaldehyde,2,4-heptadienal,linalool,nerolidol,light baking tea with high α-farnesene content,Rougui suitable for making milk tea is mellow and thick,high aroma and fired aroma,the water extract,amino acids and caffeine content in the biochemical components are low,Among the aroma components,the roasted aroma aroma is pyrazine,pyrrole,furan substances,furfural and5-methylfural content of heavy baking tea. |
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