Effects Of Withering And Shaping Techniques On The Chemistry And Qualitry Of White Tea

In this experiment, the"Chingwoo Big White"and"Fuan Big White"shoots with a bud and 2~3 leaves were used as test materials and applied to natural withering and artificial withering respectively. By sub-period sampling of withered leaf and tasting of the resulted preliminary teas, the content changes of the relative chemical compounds during withering and their effects on the preliminary tea quality were studied. The twisting and shaping experiment was also carried out on the withered leaf of the above--mentioned test materials. The results were as follows:(1)during withering, amino acids. flavone and caffeine tended to increase in contents,otherwise water extract, tea polyphenols, soluble sugar tended to decrease;(2) the chemical compounds of more increase and sharp decrease in contents were respectively flavone(natural withering Fuan Big White: 3.16%;natural withering Chingwoo Big White:1.41%"),amino acids ( artificial withering Fuan Big White: 1.3%) and tea polyphenols (natural withering Chingwoo Big White:5.87%; natural withering Fuan Big White: 5.51%), water extract (natural withering Fuan Big White: 4.49%; artificial withering Fuan Big White: 4.18%),when comparisons were made between the read—for withering leaf and finished withered leaf; (3) there were no significant difference in the effect on the variation trends of the chemical compounds contents between the two ways of withering; (4) there were more water extract, flavone, soluble sugar and"three crucial tea elements"in shaped white teas than in none—shaped ones; (5) the sensory evaluation showed that the flavors of traditional white tea were better kept in the shaped white teas ,and even by shortening the brewing time by 30%, the shaped white teas still revealed similar flavors to the none—shaped ones,suggesting that the shaping skills in this experiment could promote the thickness and duration for brewing.