Effects of New Piling Technology on Quality and Aroma of Mengding Yellow Bud

In order to realize the rapid piling of Mengding yellow bud and shorten its processing time. This study learned from the experience of traditional Mengding yellow bud processing and innovated on the materials and methods of piling, the effects of different initial piling time (60, 80 and 100 min) and repiling time (80, 100 and 120 min) on the quality and aroma of Mengding yellow bud were studied, too. The results showed that the sensory evaluation scores of initial piling time 80 min, repiling time 120 min and initial piling time 100 min, repiling time 80 min were 89.05 and 88.85 scores, which were the highest among all combinations. On the whole, while the increase of the total time of piling, the color of the soup changed from apricot green to bright yellow or light yellow to apricot yellow, and a part of theaflavins and thearubin were converted to theabrownin; the taste evolved from mellow to sweet, when the total time of piling increased from 140 to 220 min, the contents of tea polyphenols, catechins and caffeine decreased from 23.41%, 17.03%, 4.68% to 20.28%, 15.64%, 3.84%. The contents of soluble sugar and water extracts increased from 2.97%, 33.42% to 3.27%, 38.33%. The aroma changed from fragrant to sweet, the aroma components such as geraniol, dimethylvalerate, and phenylethanol were reduced, and the aroma components such as cis-4-hexen-1-ol, limonene, naphthalene, et al. were increased. This study proposed that the optimal piling time for the new Mengding yellow bud process was: initial piling time 80 min, repiling time 120 min, or initial piling time 100 min, and repiling time 80 min. The effects of different piling time on the quality and aroma components of Mengding yellow bud were also revealed.