Studies On Technology And Change Of Chemical Composition Of Oxygen Supply Fermentation Of Congou Black Tea

This article selects congou black tea as the research object, the fermentation process for the research content, add the oxygen (industrial oxygen) technology in the fermentation process, combined with traditional fermented for contrast analysis, in order to improve the quality of congou black tea, shorten the fermentation time and improve production efficiency. And research the change of the main chemicals in the fermentation process, and the effects for liquor color and aroma by oxygen supply.Compared with the traditional fermentation, the oxygen supply fermentation process speeded up the leaves surface colour turn red, promote the formation of black tea characteristic aroma, shorten the fermentation time. The oxygen supply fermentation can promote the fermentation temperature rise higher than traditional fermentation, and continue supply oxygen make the temperature drop faster and lower than traditional fermentation. The pH of oxygen supply fermentation drop faster than traditional fermentation. The oxygen supply fermentation can form theaflavins(TFs) and thearubigins(TRs) more and quickly than traditional fermentation, continue supply oxygen make the TFs and TRs reduce faster than traditional fermentation.For oxygen supply rate 5.32 L/min,select the oxygen supply time for 45 min,60 min,75 min,90 min,105min respectively as the oxygen supply fermentation experiments.There are six teams technology processing combined with traditional fermented, each group using fresh leaves 5 kg (Tea varieties was QianMei 601),as the volume dose were 0 L/kg,47.88 L/kg,63.84 L/kg,79.8 L/kg,95.76 L/kg,111.72 L/kg respectively.The tea polyphenols droped greater when the oxygen supply increased.In traditional fermentation process,the content of caffeine changed smooth,the content of free amino acid reduced,the content of water-soluble total sugar increased slowly.There were no big difference of the change of the content of caffeine, free amino acid and water soluble sugar in oxygen supply in fermentation process.TFs increased gradually in 180 fermentation times,the highest content of TFs was 1.15%. All the oxygen supply fermentation had higher content of TFs than traditional fermentation. The bigger oxygen amount, the lower TFs kept.Compared to the oxygen supply at all times,the short time oxygen supply fermentation got relatively lower TBs than traditional fermentation.Oxygen supply fermentation got the higher content of TRs than traditional fermentation, but the tendency to change was complicated.Compared to traditional fermentation, oxygen supply fermentation improved the brightness and red degree of the tea liquor color,but were inferior to the kenya black broken tea of the samples.The oxygen treatment in fermentation had obvious influence on the terpenes derivatives of tea aroma. Along with the increase of oxygen,the terpenes derivatives of tea aroma increased.The aromatic derivatives increased first,then reduced.In addition,with the increase of oxygen,the percentage content of alcohols of aroma compounds increased,Ester compounds showed obvious decreasing trend. Thus,the oxygen treatment in fermentation had obvious important influence.