| There are full of sunshine and abundant rain in the summer and autumn of China,so the tea trees grow rapidly and the yied of tea leaves is high.But the tea still have the problems such as bitter and astringent taste,low aroma.In addition,the tea is difficult to be sold and the profit margin is small.Most tea farmers would not to pick,resulting in low utilization rate of summer and autumn tea.Through the optimization design of processing technology of summer and autumn’s tea leaves.It is of great significance to improve the quality and economy effecf of summer and autumn tea.Huangjin 1 tea are the characteristics of high amino acid,high tea polyphenol,high water extract and high chlorophyll that make it become high-quality green tea seed.Due to the seasonal factors,the amino acid content in the summer’s fresh leaves of Huangjin 1 tea is lower than that in spring,and the content of polyphenols,esters catechins and flavonoids increase in summer,resulting in the bitter taste,poor aroma and low quality of green tea.Black tea,as a fully fermented tea,black tea can promote the degradation of tea polyphenols and esters catechins during the fermentation process.The solar withering and shaking of oolong tea process can also effectively reduce the bitter taste of tea soup,improve the aroma.Therefore,the solar withering and shaking are incorporated into the processing of black tea made by summer and autumn leaves of Hanjing 1 tea.Compared with the traditional process,the quality components,aroma components and enzymatic activity in the black tea made by summer and autumn leaves of Hanjing 1 tea are studied,and the quality formation mechanism of the aroma and taste of the tea is explored,forming an optimal process flow and parameters for the processing of black tea made by summer and autumn leaves of Hanjing 1 tea.The main research results are as follows:(1)Three-factor and three-level orthogonal experiments are used to optimize the processing technology of the withering way,the drying way and the raising fragrant way.The results showes that the order of influence on the quality of black tea made by summer and autumn leaves of Hanjing 1 tea under the moderate fermentation conditions is the withering way(29)the drying way(29)the raising fragrant way.The shaking 4 the withering to moisture content 62%,first drying used by automatic dryer second drying used by tea roasting machine,raising fragrant(100 ℃ 20mins)can make quality of black tea made by summer and autumn leaves of Hanjing 1 tea best.Therefore,the optimal process is regarded as the innovative process for Huangjin 1 black tea in summer and autumn.The fresh leaves→solar withering→stacking(4 times)→the withering to moisture content 62%→rolling→fermenting→first drying used by automatic dryer→second drying ued by tea roasting machine→ raising fragrant(100 ℃ 20 min).(2)During the processing of Huangjin 1 black tea in summer and autumn,the content of tea polyphenols in the innovative process showes a rising-falling trend,and the inflection point appeares in the solar withering.The polyphenol content of tea is always lower than that of traditional black tea during processing.The free amino acids in the innovative process showes a trend of rising-falling.The inflection point appeares in shaking 1.During the period from fresh leaves to shaking 2,the wip content is higher than that of traditional craft.During the period from shaking 3 to fermenting 1 hour,the wip content is lower than that of traditional process.There is not much difference in their content.During the period from fermenting 1 hour to made tea,the wip content exceedes than that of traditional process.The soluble sugar content in the innovative process showes a decreasing-increasing trend.The inflection point appeares in the first drying phase.The content is always lower than the traditional process.The variation trend of caffeine content in the innovative process is irregular "M" type during fresh leaves to the end of 4 shakes,followed by small amplitude wave type change.The content before shaking is higher than that in traditional process,and the content after shaking is lower than that in traditional process.The content of flavonoids in the innovative process generally showed the trend of "M" type change.The content before shaking 4 is higher than that in traditional process,and is lower after shaking 4 than that in traditional process.The content of water extract in the innovative process showes a rising-falling-rising trend during the processing and the inflection point appeares in the solar withering and first drying phase.The content of water extract is always lower than that of traditional process.Theaflavin and thearubigins increases during processing,and the content is always higher than that in the traditional process.(3)The changes of aroma compounds in the processing of black tea made by summer and autumn leaves of Hanjing 1 tea are reflected in the following aspects:(Ⅰ)on the aroma quantity,The innovative process showes a trend of ascending-descending.The total aroma decreases during solar withering,During the shaking period,the total amount is on the rise,and the content reaches the peak at shaking 4,which was about 1.66 times of that of fresh leaves.At the beginning of rolling,the total amount of aroma decreases,but a small peak appeares in the fermentation stage.The differences between the innovative process and the traditional process are shown that the total aroma of the innovative process is lower than that of the traditional process during solar withering shaking 1 shaking 2,and starting from shaking 3,the total aroma amount is higher than that of the traditional process.The total aroma of the innovative black tea is about 1.95 times large than that in the traditional process.(Ⅱ)In terms of aroma components,the trend of ester compounds in the innovative process is as follows: the total amount of ester compounds decreases during solar withering,and showes a rising-falling trend during shaking,and the content reaches the peak value at shaking 3,and the total amount of ester compounds increases by 2 times during shaking.From rolling,the content decreases.The content of ester compounds in the innovative process is much higher than that in the traditional process.The main trend of the content of aldehyde and ketone compounds is up from withering to fermentation and decreases after drying.In the innovative process,except for solar withering,shaking 1 and shaking 2,the total aroma of aldehydes in other stages is higher than that in the traditional process.Except shaking 2,the total aroma of ketones in other stages is higher than that in the traditional process.The content of alcohol compounds in the withering,rolling and made-tea stages is higher than that in the traditional processes.The ratio of alcohol esters in the innovative process is always lower than that in the traditional process.(Ⅲ)In terms of aroma types,except for the end of fermentation,the other process of innovative process is more abundant than the traditional process.(Ⅳ)on the aroma composition,The main difference in content is ester compounds.During processing,most of the aroma compounds,content is 1-3 times large than that of traditional process,very few aroma compounds,such as,hexyl hexanoate,trans-hexylhexanoate,2-methyl-,3-hexenyl ester,butanoic acid hexyl ester,exyl 2-methylbutanoate,(Z)-3-hexen-1-yl caproate at one stage or certain phase content can be up to five times large than that of traditional process.Except for certain stages,the contents of β-ionone and geranyl acetone are higher than those of traditional processes,and the contents of benzaldehyde from shaking 3 is higher than those of traditional processes(4)During the processing of Huangjin 1 black tea in summer and autumn,the activities of polyphenol oxidase,cellulase and glucosidase increases first and then decreases.The peak value appeares in shaking3,shaking2 and shaking1 phases respectively.The changes of traditional process and innovative process are similar,and the peak value of traditional process appears later than the innovation process,and the enzymatic activity is lower than the innovation process. |
PDF Full Text Request