“二炒”温度对传统客家炒青绿茶品质特征的影响

Effects on the quality of Hakka traditional roasted green tea by the procedure ‘the second firing'

"二炒"温度是炒青绿茶品质形成的关键,研究二炒温度对传统客家炒青绿茶品质特征形成至关重要。以梅占炒青毛茶为原料,设置3个不同的二炒温度,研究二炒温度下茶叶品质成分的变化。结果表明:二炒温度升高,茶叶中茶多酚、咖啡碱、儿茶素总量和酯型儿茶素含量均有持续减少趋势;而可溶性糖和游离氨基酸总量,随着温度升高呈现出先减后增的趋势,可溶性糖在115℃复炒时显著增加到4.31%,而后显著减少,游离氨基酸含量在115℃时显著降到2.74%,而在125℃时显著增加到4.00%;EGCG、GC含量随二炒温度的提高显著增加,C、GCG、CG含量则显著下降,当二炒温度达到125℃时,EGCG、GCG、CG、CG、ECG、EGC和EC变化并不显著,C含量则显著增加。二炒温度升高,毛茶中青气消失,火甜香增加,滋味浓厚回甘,125℃时,焦火韵味明显,茶汤鲜爽味减少。二炒以115℃3 h时茶叶品质最佳,儿茶素品质指数最大。

The temperature of ‘the second firing＇ is the key point in the process for roasted green tea. The research focused on the effect of the temperature of ‘the second firing＇ on the popular quality of Hakka traditional roasted green tea. Primary tea as the raw material was made by Meizhan, and the biochemical components were analyzed of roasted green tea after processed by three different temperatures of ‘the second firing＇. The results showed that the four components contents, tea polyphenols, caffeine, catechins and ester-catechins, had declined with the rising temperature. Soluble sugar and free amino acids contents increased and lately declined. Soluble sugar contents significantly increased to 4.31%, when the temperature reached 115℃, and then reduced. While free amino acid contents significantly decreased to 2.74% at115℃, and the contents increased significantly to 4.00% at 125℃. The content, EGCG and GC, significantly increased,with the second firing temperature increasing, while C, GCG, CG decreased. When the temperature reached 125℃, 7catechin ingredients, such as EGCG, GCG, CG, CG, ECG, EGC and EC, were not notably changed, only C had a significant increase. For primary tea, coupled with the second firing temperature rising, the smell of grass disappeared, sweetness increased with strong taste. The made tea had an unpleasant flavor and loss of fresh and heavy at 125℃. So when the primary teas are fired for three hours at 115℃, the made tea has the best quality, and catechin quality index being the maximum.