| Reprocessing,long cycle,complex production process and high cost is the characteristics of jasmine tea.Current research of jasmine tea mainly focused on the processing technology(such as traditional techniques,wet-scenting,continuous-scenting and isolation scenting),optimizing processing elements(such as water content,unit scenting flower quantity,heap of temperature,scenting time,etc.),Improving the quality of the tea and mechanism of jasminum sambac fragrant releasing and Tea fragrance absorption.Research of raw materials(tea and jasminum sambac quality)effect on flavor of jasmine tea quality is rare,and most of the jasmine tea scenting times less than 4 times,there rarely have study of high scenting times and process of microorganism change in jasmine tea scenting.This report based on the simulation system of scenting tea,to explore the tea flavor influence about quality of tea processing type,degree of fermentation,jasminum sambac quality(different regions and picking time);In combination with sensory evaluation,evaluation of different level of jasmine tea aroma quality;At the same time,explores the microorganism change in jasmine tea scenting.The results of the study are as follows:(1)Scenting jasmine tea with three different varieties of baking tea(White Milli Tea,Silver Pekoe Tea and Silver Tips Tea),the results showed that the three kinds of scented tea party detected 29 kinds of aroma substances,including the White Milli Tea 28 species,Silver Pekoe Tea 25 species,18 kinds of Silver Tips Tea,Significantly Silver Tips Tea aroma substances less than the other two samples,and Silver Tips Tea?-farnesene relative content(5.39%)less than the White Milli Tea(19.13%)and Silver Pekoe Tea(16.45%)significantly,and the relative contents of linalool(24.76%)is more than the White Milli Tea(19.51%)and Silver Pekoe Tea(23.22%),according to the quality of jasmine tea aroma evaluation index(JTF = total relative content(?-farnesene,3-Hexen-l-ol,benzoate,(Z)-+ indole + Benzoic acid,2-amino-,methyl ester)/linalool relative content),it's obviously that the Silver Tips Tea aroma quality(JTF = 0.8)less than White Milli Tea(JTF = 2.19)and Silver Pekoe Tea(JTF = 1.48).(2)Scenting jasmine tea with four different processing methods of green tea(baked,roasted,steamed and sun-greened),the results showed that there are 31 kinds of aroma substances detected from the four different tea samples,including 11 kinds of esters,4 kinds of alcohols,14 kinds of terpenes,1 kind of aldehydes and a kind of other material(indole).Including roasted Xi maojian 27 species,steamed long feng 27 species,sun-greened tea 27 species and baked White Milli Tea 29 species.4 kinds of jasmine tea in quite a number of aroma components,only difference in their content.4 kinds of jasmine tea aroma quality evaluation index(JTF)size relations as follows:Xi maojian tea(2.95)>baked baked White Milli(2.19)>sun-greened green tea(1.94)>steamed long feng(1.56).Traditional theory is that baked green tea is the best raw material,because of baked green tea with porous,large surface area,capillary abundance characteristics,therefore adsorption quantity is large,a study is given that baked green tea is the best raw material to simulate scenting jasmine tea.But the study found that roasted green tea is the best raw material to simulate scenting jasmine tea.(3)Scenting jasmine tea with black tea of fermentation entirely and compare with jasmine tea scented by unfermented green tea.The results showed that black tea aroma type and concentration significantly increased after Scenting,aroma types adds 13 kinds,concentration increased by 325%.Aroma concentration increased by223.1%,31.5%and 325%from Tea dhool to first scenting,first scenting to second scenting and Tea dhool to second scenting respectively.Concentration of total ester aroma increased by 412.1%,55.8%and 412.1%respectively;Alcohols total surface increased by 321.5%,30.1%and 321.5%respectively;Terpene class total peak surface increased by 205%.Tea aroma increased mainly comes from process adsorption fragrance of Jasminum sambac.Second scented jasmine tea JTF value(0.5)is not lower than jasmine green tea with the same scenting times JTF value(3 kinds second scented jasmine green tea JTF values were 0.42,0.38,0.50),fifth scented jasmine black tea Lapsang Souchong JTF value(1.12)is greater than the same scenting times jasmine green tea JTF value(1.004).The study shows that by jasmine tea aroma quality scenting with black tea is not lower than scenting with green tea.Integrating in different types of tea flavor composition test results analysis,because of the test samples are completely independent,so the flavor component content have bigger difference between test samples,the differences are decided by tea itself characteristics,measuring the tea quality according to flavor component contents size is not available,so the test(jasmine tea flavor component influence elements of tea types)results is given priority to with the aroma.(4)Scenting jasmine tea with different habitats and harvest time jasminum sambac respectively,jasmine tea scenting with Fuzhou jasmine flower is more than scenting with Guangxi flower in aroma concentration and ester content,but Guangxi jasmine tea terpenes content is higher than Fuzhou.Fuzhou jasmine tea JTF index(0.84)are very close to Guangxi(0.82).Flavor component content determination results show that the gallic acid content:Fuzhou Longzhu(4.57 mg/g)is higher than the Guangxi Longzhu(3.44 mg/g)about 32.8%,total polyphenols content:Fuzhou Longzhu(59.07 mg/g)is higher than the Guangxi Longzhu(47.57 mg/g)by about 24.2%,the rest of the flavor component content difference is less than 15%.The study found that scenting jasmine tea with different picking time jasminum sambac,jasmine tea aroma concentration of mid September is highest,but aroma quality of end-August is best.According to the flavor component content,3 samples in gallic acid,GC,EGC,caffeine,EC,EGCG exist significant differences on flavor component content,biggest content gap is 3.8%,16.8%,13.31%,4.8%,7.6%,18.9%respectively.No significant difference between the remaining flavor component content.(5)To seventh scented JinZhenWang jasmine tea as the research object,found that aroma type increase 14,concentration of aroma total rising by about 349.7%,esters,alcohols and terpene aroma concentration rose 675.8%,817.3%and 777.2%respectively after scented seventh times.Jasmine tea aroma quality has a positive correlativity with scenting times,the maximum JTF index is 1.43 in seventh scenting.Flavor component content determination results showed that the total flavonoids,total polyphenol,gallic acid,EGC,GCG content exist significant differences,such as content change respectively:34.7%,29.7%,22.2%,31.3%and 22.2%,and the rest of the flavor component content has no significant difference after seventh scenting.(6)The results of jasmine tea aroma component change in the scenting process shows that jasmine tea aroma types and concentration increased with scenting time,aroma increase rate is faster at the first then slower,and backed into balance after 8 hours.aroma substance increased trend is different in scenting process,increase trend of ?-farnesene and benzyl alcohol is relatively similar with aroma total concentration,increase rate is fastest in first 2 hours,then increased slower behind 8 hours;Salicylic acid methyl ester in 0?12 hours has been rising;Leaf alcohol acetate peak change trend for typical S curve;Cis-3-hexylene glycol benzoate rose fast,and then slower.(7)25 marketed different level jasmine tea aroma components were detected in this paper,at the same time has carried on sensory evaluation.The results show that the JTF index can distinguish aroma low scores(70)of tea samples better in this experiment,distinction rate was 66.7%,the distinction rate between scores in 70?85(including 85)was 53.8%,the score higher than 85 is difficult to distinguish,distinction rate was 11.7%only.Analyzing the test results only,the JTF index can be a good difference between low-grade tea in this study,and high-grade tea is difficult to distinguish,jasmine tea aroma index remains to be further improved.(8)3 endophytes were isolated from green tea,and authentication results was Curtobacterium,Sphingonomonas and Bacillus according to 16 SrRNA authentication results.No endophytic bacteria isolated from jasmine tea.Endophytic bacteria number in less related to tea production temperature of fixation and dry,and jasmine tea will be dried again to reduce water content,so it is difficult to have the endogenous bacteria. |
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