Zhang Jianyong, Mao Yuxiao, Xu Yongquan, Feng Zhihui, Wang Yuwan, Chen Jianxin, Zhao Yun, Cui Hongchun, Yin Junfeng
Tea Research Institute, Chinese Academy of Agricultural Science, Hangzhou 310008, China.
Hangzhou Academy of Agricultural Science, Hangzhou 310024, China.
Foods. 2024 Sep 20;13(18):2985. doi: 10.3390/foods13182985.
Scenting is an important process for the formation of aroma quality in floral Longjing tea. There are differences in the aroma quality of osmanthus Longjing teas processed by different scenting processes. The efficient isolated scenting method was employed to process a new product of osmanthus Longjing tea in this study, and this was compared with the traditional scenting method. The volatile compounds of osmanthus Longjing tea were analyzed by a GC-MS instrument. In addition, the effects of scenting time and osmanthus consumption on the aroma quality of Longjing tea were studied. The results indicated that there were 67 kinds of volatile compounds in the osmanthus Longjing tea produced by the isolated scenting process (O-ISP), osmanthus Longjing tea produced by the traditional scenting process (O-TSP), and raw Longjing tea embryo (R), including alcohols, ketones, esters, aldehydes, olefins, acids, furans, and other aroma compounds. The proportions of alcohol compounds, ester compounds, aldehyde compounds, and ketone compounds in O-ISP were higher than in O-TSP and R. When the osmanthus consumption was increased, the relative contents of volatile aroma compounds gradually increased, which included the contents of trans-3,7-linalool oxide II, dehydrolinalool, linalool oxide III (furan type), linalool oxide IV (furan type), 2,6-Dimethyl cyclohexanol, isophytol, geraniol, 1-octene-3-alcohol, cis-2-pentenol, trans-3-hexenol, β-violet alcohol, 1-pentanol, benzyl alcohol, trans-p-2-menthene-1-alcohol, nerol, hexanol, terpineol, 6-epoxy-β-ionone, 4,2-butanone, 2,3-octanedione, methyl stearate, cis-3-hexenyl wasobutyrate, and dihydroanemone lactone. When the scenting time was increased, the relative contents of aroma compounds gradually increased, which included the contents of 2-phenylethanol, trans-3,7-linalool oxide I, trans-3,7-linalool oxide II, dehydrolinalool, isophytol, geraniol, trans-3-hexenol, β-ionol, benzyl alcohol, trans-p-2-menthene-1-ol, nerol, hexanol, terpineol, dihydroβ-ionone, α-ionone, and β-ionone,6,10. The isolated scenting process could achieve better aroma quality in terms of the floral fragrance, refreshing fragrance, and tender fragrance than the traditional scenting process. The isolated scenting process was suitable for processing osmanthus Longjing tea with high aroma quality. This study was hoped to provide a theoretical base for the formation mechanism and control of quality of osmanthus Longjing tea.
窨制是花香型龙井茶叶香气品质形成的重要过程。不同窨制工艺加工的桂花龙井茶叶香气品质存在差异。本研究采用高效隔离窨制方法加工桂花龙井新产品，并与传统窨制方法进行比较。采用气相色谱-质谱联用仪分析桂花龙井茶叶的挥发性化合物。此外，研究了窨制时间和桂花用量对龙井茶叶香气品质的影响。结果表明，采用隔离窨制工艺（O-ISP）生产的桂花龙井茶叶、传统窨制工艺（O-TSP）生产的桂花龙井茶叶和原料龙井茶叶胚（R）中含有67种挥发性化合物，包括醇类、酮类、酯类、醛类、烯烃类、酸类、呋喃类等香气化合物。O-ISP中醇类化合物、酯类化合物、醛类化合物和酮类化合物的比例高于O-TSP和R。随着桂花用量增加，挥发性香气化合物的相对含量逐渐增加，其中包括反式-3,7-氧化芳樟醇II、脱氢芳樟醇、氧化芳樟醇III（呋喃型）、氧化芳樟醇IV（呋喃型）、2,6-二甲基环己醇、异植物醇、香叶醇、1-辛烯-3-醇、顺式-2-戊烯醇、反式-3-己烯醇、β-紫罗兰醇、1-戊醇、苯甲醇、反式-p-2-薄荷烯-1-醇、橙花醇、己醇、松油醇、6-环氧-β-紫罗兰酮、4,2-丁酮、2,3-辛二酮、硬脂酸甲酯、顺式-3-己烯基异丁酸酯和二氢银莲花内酯的含量。随着窨制时间增加，香气化合物的相对含量逐渐增加，其中包括2-苯乙醇、反式-3,7-氧化芳樟醇I、反式-3,7-氧化芳樟醇II、脱氢芳樟醇、异植物醇、香叶醇、反式-3-己烯醇、β-紫罗兰醇、苯甲醇、反式-p-2-薄荷烯-1-醇、橙花醇、己醇松油醇、二氢-β-紫罗兰酮、α-紫罗兰酮和β-紫罗兰酮的含量。与传统窨制工艺相比，隔离窨制工艺在花香、清香和嫩香方面能达到更好的香气品质。隔离窨制工艺适合加工香气品质高的桂花龙井茶叶。本研究希望为桂花龙井茶叶品质形成机制及品质控制提供理论依据。
