Effect of Low Temperature Treatment on the Quality of Jinxuan White Tea in the Early Stage of Fresh Leaves Withering

In order to explore the effect of low temperature treatment on the quality of Jinxuan white tea in the early stage of withering, the fresh leaves of Jinxuan tea variety with one bud and two leaves were used as raw materials. In the early stage of withering, the smart refrigerator was used for low temperature and different length treatment. The white tea was made according to the indoor natural withering and drying process. The aroma and taste of white tea were analyzed by sensory evaluation, gas chromatography-mass spectrometry and electronic tongue. The results showed that the quality of white tea processed at low temperature (5 ℃) treatment in the early withering stage was significantly different from that of the control. Low temperature treatment improved the persistence of white tea aroma and the intensity of sweet aroma and flower aroma, and increased the types and contents of fragrant volatile substances. The white tea treated at 5 ℃ for 40 h increased 21 kinds of fragrant volatile substances compared with the control. The total amount of fragrant volatile substances of white tea treated at 5 ℃ for 30 h increased the most, about 5 times that of the control. At the same time, low temperature treatment could increase the alcohol thickness of white tea taste and reduce the bitter taste. The taste sweetness of white tea treated at 5 ℃ for 50 h was the highest, which increased by 7.28% compared with the control. Therefore, low temperature treatment in the early stage of fresh leaves withering was helpful to improve the quality of Jinxuan white tea. The best comprehensive quality was the white tea treated at 5 ℃ for 30 h.