不同渥堆发酵方法对普洱茶品质的影响

Effects of different pile-fermentation methods on the quality of Pu-erh tea

中文关键词:  普洱茶  传统渥堆发酵  数控渥堆发酵  气相色谱-质谱法  高效液相色谱法  电子鼻

英文关键词:Pu-erh tea  traditional pile-fermentation  numerical control pile-fermentation  gas chromatography-mass spectrometry  high performance liquid chromatography  electronic nose

中文摘要:

      目的 研究不同渥堆发酵方法对普洱茶品质的影响。方法 以三级晒青茶为原料, 分别以高效液相色谱法(high performance liquid chromatography, HPLC)、气相色谱-质谱法(gas chromatography-mass spectrometry, GC-MS)、电子鼻结合感官审评方法对比数控渥堆发酵及传统渥堆发酵对普洱茶品质的影响。结果 主成分分析(principal component analysis, PCA)及聚类分析结果表明, 两种渥堆发酵出堆样的香气有差异, 但差异不明显。传感器区别贡献率分析(Loading)结果表明, 甲基类(W1S)、硫化物类(W1W)对香气测定的贡献率最大, 且对数控渥堆发酵出堆的贡献率大于传统渥堆发酵; GC-MS结果表明数控渥堆发酵出堆样的甲氧基类含量高于传统渥堆发酵, 进一步佐证了感官审评中数控渥堆发酵出堆样陈香更浓郁。聚类分析和感官审评结果表明, 数控渥堆发酵更利于品质稳定的普洱茶的形成。HPLC结果表明, 两种渥堆发酵方式的化学物质变化规律基本相同, 但数控渥堆发酵出堆样的氨基酸、茶多酚、水浸出物及没食子酸含量显著低于传统渥堆发酵(P<0.05), 总儿茶素及咖啡碱含量差异不显著(P>0.05), 进一步佐证了感官审评传统渥堆发酵滋味更醇厚。结论 数控发酵可加工几十千克至数吨茶叶, 加工周期短, 且发酵过程中品质变化稳定性比传统发酵好, 传统发酵滋味比数控发酵滋味醇厚度高且化学成分含量高于数控发酵, 但继续摸索数控发酵技术的参数设置, 可以弥补这一缺点。

英文摘要:

      Objective To study the effects of different pile-fermentation methods on the quality of Pu-erh tea. Methods Three-level sun-dried green tea was used as raw material, high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and electronic nose combined with sensory evaluation were used to compare the effects of numerical control (NC) pile-fermentation and traditional pile-fermentation on the qualities of Pu-erh tea. Results Principal component analysis (PCA) and cluster analysis showed that there were differences in the aroma of the 2 kinds of fermentation piles, but the differences were not significant. Sensor difference contribution analysis (Loading) showed that methyls (W1S) and sulfides (W1W) contributed the most to the aroma determinationl, and the contribution to the NC pile-fermentation was greater than that of traditional pile-fermentation; GC-MS analysis showed that the methoxyl content of the NC pile-fermentation pile sample was higher than that of the traditional pile-fermentation, which further supported the stronger aging aroma of the NC pile-fermentation sample in the sensory evaluation. Cluster analysis and sensory evaluation showed that NC pie-fermentation process was more conducive to the formation of Pu-erh tea with stable quality. HPLC showed that the change patterns of chemical substances were the same between the 2 types of fermentation methods, but the content of amino acids, tea polyphenols, water extracts and gallic acids in the NC pile-fermentation was significantly lower than those of traditional pile-fermentation (P<0.05), and the differences in the content of total catechins and caffeine was not significant (P>0.05), further supporting the sensory evaluation of the taste of traditional fermentation was mellower than that of NC pile-fermentation. Conclusion NC pile-fermentation can process dozens of kilograms to several tons of tea, with a shorter processing cycle and the stability of quality change during fermentation is better than traditional pile-fermentation, the traditional fermentation taste thicker and the chemical composition content is higher than that of NC pile-fermentation, but the parameter setting of NC pile-fermentation technology can make up for this shortcoming.