【作者】 江丽萍；

【导师】 金心怡；

【作者基本信息】 福建农林大学 ， 茶学， 2009， 硕士

【摘要】 萎凋是形成白茶的关键工序。现有的白茶萎凋工艺存在着历时长、用工量大、劳动强度高、耗能高的问题,研究白茶萎凋新工艺对进一步提高白茶品质和工效,降低劳动成本具有重要意义。为此,本文对以日光为能源的白茶萎凋房以及能自动进行日光和自然萎凋的交替连续萎凋设备进行了较为系统的试验研究。通过白茶日光萎凋与自然萎凋的对比试验结果表明,采用日光萎凋工艺氨基酸和可溶性糖保留量较多,茶多酚和黄酮含量保留量较少。审评结果表明,日光萎凋毛茶总分比自然萎凋高2.7分,氨基酸和可溶性糖是构成白茶茶汤鲜爽和甜醇的重要成分,因此日光萎凋比自然萎凋更有利于白茶生理生化变化,具有显著的优越性。本文从太阳高度角、厂址北纬度、采光度等方面分析了日光萎凋房的方位及萎凋房采光屋面倾角,分析计算结果表明,日光萎凋房方位为南北走向,萎凋房屋面倾角为22°。通过日光萎凋房性能试验结果表明,在任何时间段,萎凋房内部的温度皆高于室外温度,说明PC板为覆盖材料的日光萎凋房具有良好的保温蓄热性能,基本满足白茶萎凋的温度要求。通过对日光萎凋房的同一水平面、垂直面的温度、相对湿度、风速的变化进行了较为系统的测定,结果表明,萎凋设备内各点相对湿度值和风速值存在一定的差异。对日光连续萎凋方式应用效果进行试验研究,结果表明:(1)通过对不同气候条件下的日光连续萎凋方式的试验结果表明:在阴雨天气,日光萎凋房的萎凋环境温度平均值比外界温度高2.83℃,两者差异达到极显著水平;在晴天中午前后,应采取适当的遮阳措施,以降低日光萎凋房内的温度,避免温度过高影响白茶萎凋质量;在自然通风的条件下,日光萎凋房的排湿效果尚不显著。(2)对不同萎凋方式的白茶萎凋过程的水分变化测定结果表明,日光连续萎凋的失水速率呈现“慢—快—慢”的变化趋势。在晴天条件下,萎凋失水速率快慢顺序为:人工复式竹席萎凋>日光连续萎凋>人工复式竹帘萎凋,日光连续萎凋的失水速率介于竹席、竹帘人工复式萎凋之间;在雨天条件下,萎凋失水速率快慢顺序为:日光连续萎凋>人工复式竹席萎凋>人工复式竹帘萎凋。在连续萎凋机上进行不同摊叶厚度的试验结果表明,不同摊叶厚度失水速率快慢顺序为:晴天条件下,萎凋机摊叶厚度A1(1.00kg/筛)>CK>萎凋机摊叶厚度A2(1.25 kg/筛)>萎凋机摊叶厚度A3(1.50kg/筛);雨天条件下,CK >萎凋机摊叶厚度A1’(0.75 kg/筛) >萎凋机摊叶厚度A2’(1.00 kg/筛)>萎凋机摊叶厚度A3’(1.25 kg/筛)。(3)生化分析结果表明,采用日光连续萎凋茶多酚和黄酮保留量最少,氨基酸可溶性糖含量介于人工复式竹帘萎凋和人工复式竹席萎凋之间。方差分析结果表明,日光连续萎凋与人工复式萎凋方式对氨基酸和黄酮含量变化差异达到显著水平,对可溶性糖和茶多酚含量变化差异不显著。毛茶审评结果表明,日光连续萎凋毛茶品质基本达到人工复式竹帘萎凋的水平。日光连续萎凋设备不同摊叶量毛茶感官审评内质得分排序为:4-9批次茶:CK>A2>A1>A3;4-12批次茶:CK>A2’>A1’>A3’。结合能源利用角度和毛茶审评结果,晴天以A2(1.25Kg/筛)摊叶厚度适宜,雨天以A2’ (1.00 Kg/筛)摊叶厚度适宜。(4)通过对日光萎凋房及连续萎凋设备经济性分析结果表明,采用日光连续萎凋方式与加温萎凋相比,年运行费用可节省54644.40元;而采用加温萎凋比日光连续萎凋制毛茶节约5.11-4.90=0.21元/Kg。从节约能源、提高品质、节省劳力的角度考虑,日光连续萎凋技术具有广阔的应用前景。更多还原

【Abstract】 Withering is the key process during white tea process. However, the current withering process exists many problems of long duration, labor-intense, inefficient and high energy-consuming. Therefore, study on the new withering process of White tea has great significance not only for improving tea quality and efficiency, but also for reducing labor cost. The article carrys on systematic reasearch to the facilities which used sunshine as energy source and continuous equipment which can conducted sunshine withering and natural withering automatically of White tea.The article set the contrast test between sunshine withering and natural withering, the result shows that using sunshine withering makes the remain dose of AA and TPS is more than using natural withering, but the remain dose of TP and Flavones is less. The result of sensory quality shows that the raw tea of sunshine withering getting 2.7 point than natural withering, AA and TPS are the important composition of fresh and mellow of White tea. so sunshine withering is good for the change of physiology and biochemical of White tea and it has significant superiority.The article analysis on the solar altitude and orientation from the perspective of sun elevation angle, north latitude of plant site and the extent of lighting. The result shows that the orientation should be North South and the roof angle should be 22°, and the rusult also shows that the temperature in the sunshine room is higher than outside at any time, it means the sunshine withering room which used PC board as covering material has good performance of isolation and heat storage, and it preliminary meet the temperature demand of withering. Through systematic determine to the temperature, relative humidity and the wind wind of same level and vertical plane, the result shows that the relative humidity and the wind speed exist difference.Through the experimental study on sunshine continuous withering method and its application effect,the result shows that :(1) The testing results the sunshine continuous withering method of different climate condition indicate:the aveage is 2.83℃higer than outside in the rainy day, and their difference reach level of significance. In sunny day at about noon, it needed to take proper measure of shading to decrease the temperature in the withering room, and avoid harmful influence on the tea quality which caused by overhigh temperature.The effect of humidity elimination is not significance in the conditon of natural ventilation, it neet to equip with a fan to improve the environment.(2) The testing results the change of moisture of different withering method:the dehydrating rate present the trend of“low-fast-low”, The dehydrating rate ranking is manual combined withering by bamboo mat > sunshine continuous withering > manual combined withering by bamboo curtain in sunny day; and in rainy day, the ranking is sunshine continuous withering > manual combined withering by bamboo mat > manual combined withering by bamboo curtain.The testing results the ranking of different spreading thickness in the continuous withering equipment. In sunny day, A1(1.00kg/sieve)> CK > A2(1.25 kg/ sieve)> A3(1.50kg/sieve); In rainy day, CK > A1’(0.75 kg/ sieve) > A2’(1.00 kg/sieve)> A3’(1.25 kg/ sieve)。(3)The biochemical analysis result shows that: the remain dose of TP and Flavones is least of sunshine continuous withering,the remain dose of AA and TPS is between manual combined withering by bamboo curtain and manual combined withering by bamboo mat. The result of variance analysis shows that the difference of AA and Flavones reachs level of significance, and the remain dose of TP and TPS had not significant difference.The result of sensory quality shows that the quality of sunshine continuous withering reaches level of manual combined withering by bamboo curtain, the score ranking: CK>A2>A1>A3(April,9th); CK>A2’>A1’>A3’ (April,12nd). Consider with energy utilization and result of sensory quality, in sunny day the spreading thickness choose A2(1.25Kg/sieve), and in rainy day choose A2’ (1.00 Kg/sieve).(4) The testing results the economic analysis of sunshine withering room and continuous withering equipment indicate: the operation cost of sunshine withering method could save $ 54644.40yuan and the cost of raw tea could save $ 0.21yuan perkilo.Consider the energy saving, quality improving and labor saving, the method of sunshine withering method has wide application prospect.更多还原