Biochemical components and aroma components variation of Liudong wild kungfu black tea in Guangxi during processing

ObjectiveDynamic changes of quality components in kungfu black tea during processing were studied in order to explore the suitable processing parameters for wild kungfu black tea, and provide reference for processing technol-ogy improvement of Guangxi wild kungfu black tea. MethodLiudong wild tea fresh leaves with one bud two leaves in Xing'an, Guangxi were taken as raw materials. Samples were taken from withered leaves, rolled leaves, leaves fermented for 1,2,3,4 and 5 h, and dried. 3 g black tea was taken from the samples and brewed with 150 mL water for 5 min. Senso-ry evaluation was conducted on kungfu black tea and variations of major biochemical components and aroma components were analyzed. ResultSensory score for black tea made after 4 h fermentation was the highest (92.5). The soup color was bright and red, it emanated floral and sweet fragrance. The tastes was mellow and leaf base was bright. During the process-ing, free amino acids and caffeine contents showed a decreasing trend. Free amino acids content declined from 5.20% in withered leaves to 4.10%, and caffeine content decreased from 5.23%in withered leaves to 4.74%. Tea polyphenol content was in an up-down trend and reached the peak in rolled leaves(25.40%). Theaflavin and thearubigin contents also went through an up-down variation, and reached the maximum at 4 h fermentation(0.50%for theaflavin and 4.20%for thearubi-gin). Theabrownin content increased from 1.30%in withered leaves to 6.00%at 5 h fermentation. Among the aroma compo-nents, relative percentage contents of alcohols and hydrocarbons decreased while aldehydes and esters increased as fermen-tation time extended. The major components that affecting the aroma of Liudong kungfu black tea included geraniol (25.55%), methyl salicylate(20.55%),β-linalool(14.75%), benzaldehyde acetaldehyde(5.14%), 2-acetylfuran(2.76%), phenylethyl alcohol (2.19%) and linalol oxideⅡ(2.04%). ConclusionLiudong wild kungfu black tea in Guangxi contains aromas like rose, sweet flower and holly. The black tea made after 4 h fermentation has the best quality.