不同干燥温度对普洱茶多酚类物质和香气成分的影响

The Effect of Different Drying Temperatures on the Transformation of Polyphenols and Volatile Aroma Components in Pu-erh Tea

本文研究了添加丙氨酸和木糖促进普洱茶的发酵进程,并探索了不同干燥温度(晾干、40℃、60℃、80℃、100℃、120℃)对出堆普洱茶品质及香气成分的影响。实验表明,不同温度干燥处理,对普洱茶多酚类物质的转化具有不同影响。60℃以下的低温干燥组茶多酚、儿茶素、茶褐素含量均较高,而高于80℃的高温干燥组各成分含量明显较低。挥发性香气成分分析表明,各组普洱茶主要香气成分总体一致,主要有(+)-环蒜头烯、己醛、庚醛、5-甲基糠醛、苯甲醛、苯乙醛、天然壬醛等。低温干燥组(晾干、40℃、60℃)的香气成分中烯烃类物质所占百分比较大,高温干燥组(80℃、100℃、120℃)中醛类物质所占百分比较大。低温干燥组的苯环化合物和杂环化合物香气成分均高于高温干燥组,晾干组最高。综合而言,晾干普洱茶品质最佳,60℃以下干燥处理的普洱茶具有较好的品质。

Acceleration of the fermentation of pu-erh tea by the addition of alanine and xylose was analyzed; in addition, the effect of different drying temperatures(air-drying at, and drying at 40 ℃, 60 ℃, 80 ℃, 100 ℃, and 120 ℃) on the quality and volatile aroma components of Pu-erh tea following pile fermentation were explored in this study. Drying at different temperatures was observed to have different effects on the transformation of polyphenols. The tea polyphenol, catechins and theabrownins content in Pu-erh tea was higher in the low-temperature drying group(below 60 ℃) than in the other groups; however, the polyphenol content was significantly lower in the high-temperature drying group(above 80 ℃) than in the other groups. Analysis of the volatile aroma components of Pu-erh tea revealed similarities in the major aroma components in each temperature group; these included(+)-cyclosativene, hexanal, heptanal, 5-methyl furfural, benzaldehyde, phenylacetaldehyde, and natural nonylaldehyde. The aroma components of Pu-erh tea dried at low-temperatures(air-drying, 40 ℃ and 60 ℃) showed a relatively high percentage of olefins, while tea dried at high temperatures(80 ℃, 100 ℃, and 120 ℃) displayed relatively higher aldehyde content. The low-temperature drying group displayed a relatively higher percentage of benzene-related and heterocyclic aroma components than the high-temperature drying group; the highest percentage was observed in the air-drying group. In general, the quality of air-dried Pu-erh tea was determined to be the best, and good quality Pu-erh teas were those dried at temperatures below 60 ℃.