广西六垌野生工夫红茶加工过程中生化成分及香气成分变化趋势分析

【目的】研究工夫红茶品质成分在加工过程中的动态变化,探索野生工夫红茶适宜的加工工艺参数,为广西野生工夫红茶的加工技术优化提供参考依据。【方法】以广西兴安六垌野生茶一芽二叶鲜叶为原料,分别在萎凋叶、揉捻叶及发酵1、2、3、4、5 h时取样烘干,取3 g红茶与150 mL水冲泡5 min,对工夫红茶进行感官审评,并分析其主要生化成分及香气成分变化趋势。【结果】鲜叶发酵4 h时制成的工夫红茶感官评分最高(92.5分),红茶汤色红亮,花香、甜香浓,滋味醇厚,叶底红匀、亮。在工夫红茶加工过程中,游离氨基酸和咖啡碱含量呈降低趋势,分别从萎凋叶的5.20%和5.23%降至4.10%和4.74%;茶多酚含量呈先升后降趋势,揉捻叶时含量最高(25.40%);茶黄素和茶红素含量也呈先升后降趋势,均在发酵4 h时达最高值(0.50%和4.20%);茶褐素含量呈直线上升趋势,由萎凋叶的1.30%上升到发酵5 h的6.00%。红茶香气成分中,醇类和碳氢化合物相对百分含量随发酵时间的延长呈降低趋势,醛类和酯类相对百分含量呈上升趋势。影响广西六垌野生工夫红茶香气的主要成分有香叶醇(25.55%)、水杨酸甲酯(20.55%)、β-芳樟醇(14.75%)、苯乙醛(5.14%)、2-乙酰基呋喃(2.76%)、苯乙醇(2.19%)、氧化芳樟醇Ⅱ(2.04%)等。【结论】广西六垌野生工夫红茶具有玫瑰花香、甜花香、略带冬青香的品质特征,以发酵4 h制成的红茶品质最佳。

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

Objective]Dynamic 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. Method]Liudong 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. Result]Sensory 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%). Conclusion]Liudong 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.