不同干燥方式对普洱茶香气的影响研究

Effect of Drying Methods on the Aromatic Character of Pu-erh Tea

采用顶空固相微萃取技术提取进行晾干、晒干、烘干处理后的普洱茶香气成分,经气质联用进行分析鉴定,探讨干燥方式对普洱茶香气的影响。结果晾干茶样中共鉴定分离出34种化合物,占总检测量94.78%,其中萜烯、醇类含量较低,酯类含量高,在晾干样品中检测出对普洱茶的陈香有贡献的的联苯芳香烃,此类物质在晒干和烘干样品中未检出;晒干样中共鉴定分离出27种化合物,占总检测量95.72%,其中酮类物质含量较高,酯类含量低。烘干样品中共鉴定分离出22种化合物,占总检测量95.86%,其中醇类含量高,主要是环氧芳樟醇、α-萜品醇、2-羟基-3,5,5-三甲基-环己-2-烯酮等带有甜花香和焦糖香的香气组分。感官审评表明,晒干茶样带有日晒气、辛辣味;烘干的则带有烘烤香;晾干的香气较纯正陈香显露。可见,不同干燥方式,香型特征差异较大,晒干、烘干这两种干燥方式形成的茶叶香气,不符合普洱茶陈醇的香型特征,普洱茶干燥宜采用晾干方式。

With the aim to study the effect of drying methods on the aroma Characteristics of Pu-erh tea, the headspace solid-phase microextraction （HS-SPME） coupled with capillary gas chromatography-mass spectrometry （GC-MS） was used for the determination of volatiles in Pu-erh tea dried by baking, air-drying and sun-drying respectively. Results showed： Thirty-five compounds representing 95.4% of aroma contents of air-dried sample were identified with lower contents of terpenes and alcohols but higher contents of esters. Some biphenyls compounds which contributed to the stale odor of Pu-erh tea were distinct compounds of the air-dried sample. As for the sun-dried sample, Twenty-eight compounds representing 96.5% of aroma contents were identified with higher contents of ketones and lower contents of esters. In the baked sample, Twenty-four compounds representing 98.6% of aroma contents were identified with more alcohols compounds such as epoxylinalol, α-terpineol, 2-hydroxy-3,5,5-trimethyl-cyclohex- 2-enone contributed to the camerlsed and sweet flower odor of tea. The results were consistent with that of sensory tests. Sensory tests showed： The characteristic aroma of sun-dried tea, baked tea and air-dried tea were pungent, high-fired and stale odour, respectively. Results showed both baking methods and sun-drying methods were not suitable for Pu-erh tea, but the air-drying methods were the best method of the formation of Pu-erh tea aroma.