原料茶干燥工艺对绿茶饮料品质的影响

为探明饮料用原料茶的适宜干燥工艺,将不同干燥方式、干燥程度绿茶原料加工成茶饮料,研究其浸出特性及品质稳定性。结果表明:(1)低温浸提时,茶多酚浸出量以炒干最高,高温时以烘炒焙、烘炒烘处理最高。氨基酸的浸出量则均以烘干、烘焙处理最高。(2)烘干、烘焙样品在灭菌前后及贮藏期间的L值显著为高,平均值较其余处理高2.035~3.905;抗色变能力同样以烘干较强,低温贮藏时的-a/b值较炒干处理样高19.5%。(3)感官风味比较显示,大多数处理茶汤在灭菌后均呈现出绿黄或黄绿色,香气带熟,但烘干处理仍能保持绿明亮,且滋味、香气未显熟味;贮藏期间的风味稳定性也以烘干样为最佳。综合分析,饮料用原料茶的干燥工序宜采用烘干工艺,且烘干程度以5%~6%为佳。

Effect of Different Drying Technologies during Raw Tea Processing on the Quality of Green Tea Beverage

To explore the appropriate drying technology during raw tea processing, leaching behaviors and quality stabilities of tea samples prepared from raw materials dried by different methods or degree of drying were compared. The results revealed that (1) Raw tea dried by frying showed the highest contents of tea polyphenols when processed under low temperature, whereas those dried by baking-frying, or baking-frying-backing showed the highest contents of tea polyphenols when processed under high temperature. (2) In respect of color stability, tea soup prepared from baking-dried tea showed significantly elevated L value after sterilization or during storage, with the average L value increased by 2.035-3.905. Meanwhile tea soup prepared from baking-dried tea also showed higher anti-discoloration, with a/b value during low-temperature storage increased by 19.5%. (3) In respect to sensory flavor, most tea soups showed yellow-green color and ripe aroma while tea samples processed by baking-drying remained green, bright and fresh without any ripe taste. Besides, tea samples processed by baking-drying also showed superior flavor stability during storage irrespective of temperatures. In conclusion, baking approach during raw tea process was proposed withthe optimized drying content between 5%-6%.