夏秋绿茶色泽提升技术研究
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摘要
茶叶含有丰富的有益于人体健康的营养成分和疗效成分,是世界三大无酒精饮料之一,也是中国的国饮和传统的出口商品。随着社会的快速发展,人们生活水平的提高,人们的消费水平也随之提高,这就产生“高档茶畅销、低档茶滞销”的现象。目前,传统名优绿茶生产加工仅限于春季,但春季生产季短,原料有限,难以形成批量生产来满足市场需求。这就要求打破春季绿茶的局限,加大其它季节绿茶的开发力度。相对春茶,夏秋茶生产期长,热量条件丰实,茶树生长快,发展潜力很大。然而,夏秋茶味苦涩,味阀值高,色泽暗沉。夏秋绿茶的品质提升,能较大程度的增加资源利用率,提高茶叶价格,有切实的经济效益。干茶色泽、汤色、叶底色泽在茶叶感官品质八项因子中占三项,一定程度上反映了绿茶品质的好坏。对夏秋绿茶色泽品质的提升,无论是提高整体产品质量,还是促进茶叶销售都非常重要。
     本试验把真空冷冻干燥技术运用到茶叶加工中。采用夏秋季节成品茶复水后,比较真空冷冻干燥技术、微波干燥技术、烘干技术、远红外干燥技术对茶叶色泽的提升效果,结合感官审评、色差测定以及化学成分分析,探讨真空冷冻干燥提升茶叶色泽的机理。正交试验确定真空冷冻干燥技术在绿茶加工中的最佳参数条件,对真空冷冻干燥之后的后续干燥方式进行选择。以龙井43茶青为原料应用冻干的最佳工艺和最佳后续干燥方式进行叶茶和碎茶的试验。得出以下结论:
     1、茶样复水后经过真空冷冻干燥、微波干燥、烘干、远红外干燥的比较发现:真空冻干的干茶和叶底-a/b值高于其它样。感官审评中,真空冷冻干燥茶样的外形色泽和叶底色泽优于其它处理,显著优于未处理样。真空冷冻干燥样的审评总分显著高于未处理样。经过处理的茶样水浸出物、游离氨基酸、茶多酚含量减少,酚氨比低于未处理样,处理间差异不显著。真空冻干样的黄酮总量与黄酮苷的含量均显著高于未处理样和其它处理,而叶绿素a,叶绿素b,总叶绿素含量均低于未处理样。真空冻干利于茶样干茶色泽和叶底色泽的提升,总体品质部分提升,滋味品质保持。黄酮总量和黄酮苷组分含量的增加对茶样干茶和叶底色泽改善有一定的作用。推测复水处理使得茶样的黄酮及其苷类物质大部分浸出在茶叶表面,而真空冷冻干燥对这些物质最大限度的保持,避免了高温的破坏。
     2、冻干参数研究的试验中,茶叶含水量为最主要因素,茶叶含水量对茶样外形色泽,叶底色泽,汤色亮度,汤色绿度,干茶亮度,干茶绿度均有较大影响。冻干时间对干茶亮度和茶汤亮度影响较大,冻干机预冻温度和茶叶复水水温对叶底颜色影响较大。数据显示含水量45%,冻干时间3h,干茶与叶底的-a/b值最好,绿度最高。冻干机预冻温度和茶叶复水水温对试验结果影响不大,分别取预冻到-25℃和复水水温25℃。从冻干的后续干燥试验得知,各处理样的茶汤,干茶的绿度没有明显差异。感官审评汤色,总分以烘干的最好,选择烘干的干燥方式。
     3、采用龙井43制得的碎茶中,经过微波杀青揉切真空冷冻干燥的茶样外形和汤色得分,叶底的-a/b值显著高于其它,感官审评总分各处理无显著差异。微波杀青揉切真空冷冻干燥利于茶叶色泽的优化,特别是干茶色泽和汤色,以及叶底的绿度得改善。同时,冻干处理对茶叶总体品质不造成影响。
     4、采用龙井43制得的叶茶中,微波杀青重揉捻烘干后再复水真空冷冻干燥的茶样干茶外形色泽显著优于未复水样,干茶的-a值以及-a/b值显著高于其它,其感官审评总分增加不明显,内含物质与其它处理略有差别,其中咖啡碱增加明显。叶茶微波杀青重揉捻烘干后再复水真空冷冻干燥利于茶叶干茶色泽的保持,其外形色泽和干茶绿度有较大的提升,推测是复水后黄酮类水溶性色素溶解于茶叶表面,真空冷冻干燥使茶叶色素有很好的保持。
Rich in nutritious and efficacious ingredients to human health, tea is one of the world's three non-alcoholic beverageswhich is also China's national drink and the traditional export commodities. With the rapid development of society and people's living standards, the phenomenon of "high-grade tea is best seller, low-grade tea is dead stock" appeared. At present traditional famous green tea is often made in the spring, but the production season is short, raw material is difficult to meet market demand. Improving the quality of summer-autumn tea can increase resource utilization and tea prices, which create real economic benefits. To a certain degree, color of dry tea, soup and infused leaf reflect the quality of green tea. With the development of quality of summer-autumn tea, tea sales will become very easy.
     In this study, the vacuum freeze-drying technology was applied to tea processing. After summer-autumn tea rehydrate, in order to enhance the color of tea, compared vacuum freeze-drying, microwave drying, drying and far infrared drying technology, combined with sensory evaluation, color determination and chemical composition analysis, and investigated vacuum freeze-drying mechanism. The best parameters in green tea processing by vacuum freeze-drying technology were determined by orthogonal experiment. Longjing 43 is fresh tea leaves as raw material, which was used to do the test about tea and broken tea by the application of freeze-drying and the best way of follow-up drying. The conclusions are as follows:
     1.After tea samples rehydrate, compared vacuum freeze-drying, microwave drying, drying and infrared drying method found that:the-a/b value of dry tea and infused leaf are higher than the other samples by the vacuum freeze-drying. In the sensory evaluation, the color of tea samples by vacuum freeze-drying is better than other and is significantly better than CK, but water extractum and phenol ammonia ratio is lower than CK; The total flavonoids and flavonoid glycosides are higher than CK, and chlorophyll a, chlorophyll b, total chlorophyll content are lower than CK. Vacuum freeze-drying is propitious to color, total flavonoids and flavonoid glycosides enhancement.
     2.In the lyophilization experiment, the moisture content of tea is most important factors. Drying time have a greater impact on the brightness of dry tea and soup, freeze dryer pre-freezing temperature and water temperature have a greater impact on tea leaves color. The results showed that the optimal conditions is moisture content 45%, drying time 3 h. Freeze dryer pre-freezing temperature and rehydration temperature of tea has little effect on the experimental results.
     3.The broken tea was made by Longjing 43, which shape and soup color, the-a/b values of infused leaf are better than the other by microwave deactivation of enzymes, rolled and vacuum freeze-drying. The total points have no significant difference by sensory evaluation. Microwave deactivation of enzymes, cut and vacuum freeze-drying are in favor of the color of tea, especially the color of dry tea and soup.
     4.The shape and color of tea samples that is longjing43 is better than nonrehydration samples by microwave deactivation of enzymes, re-rolled and then vacuum freeze-drying, the -a and -a/b value of dry tea was significantly higher than the other, its sensory evaluation scores have no significant increase. Contains material are slightly different, in which caffeine increases. The color of dry tea can maintain by microwave deactivation of enzymes, re-rolled and then vacuum freeze-drying and then rehydration.
引文
[1]任为民,李代明.试谈夏秋茶低产问题与增产途径[J].四川农业科技,1991(3):39.
    [2]毕彩虹.设施栽培条件下优质绿茶的品质变化研究[D].西南大学,2007.
    [3]毕彩红.夏秋绿茶的发展及前景探讨[J].茶业通报,2007.29(3):109-111.
    [4]游小妹.绿茶品质常见的缺陷及成因[J].茶叶科学技术,2000,(3):30-31.
    [5]陈杖洲.夏秋茶品质的形成与特征[Z].茶苑,2(X)3.
    [6]康孟利,薛旭初.中国茶叶加工的发展趋势[J].宁波农业科技,2007,(1):11-12,23.
    [7]王文杰.茶叶色泽研究概况及其前景[J].福建茶叶,2003(4):31-32.
    [8]钟映富,姚勇芳,李中林,等.杀青对绿茶色泽品质的影响[J].广东轻工职业技术学院学院,2003,2(3):22-24.
    [9]邱瑞瑾,王登良,徐文贤,等.绿茶色泽的形成机理及调控[J].广东茶业,2007(5):14-16.
    [10]郑红发,李赛君,黄怀生,等.优质绿茶生产的理论与实践IV湖南绿茶品质特点和关键加工技术[J].茶叶通讯,2009,36(1):3-10.
    [11]王润龙,粟本文,陈江涛.提高名优绿茶色泽的加工技术措施[J].茶叶通讯,2007,34(2):35-36.
    [12]倪德江,陈玉琼,袁芳婷等.绿针茶加工过程中叶绿素的变化与色泽品质的形成[J].华中农业大学学报,1996,15(6):594-597.
    [13]宛晓春.茶叶生物化学[M].北京:中国农业出版社,2003,15-306.
    [14]朱博.绿茶茶汤色泽的变化规律及其调控研究[D].安徽农业大学,2009.
    [15]杨昌举.茶多酚与茶叶品质的关系[J].食品科学,1985,(5):2-6.
    [16]朱博,夏涛,高丽萍等.绿茶茶汤中黄酮醇及其苷类的测定方法以及对茶汤色度的影响[J].食品与发酵工业,2009,35(2):146-147.
    [17]中川致之.化学のてみた绿茶煎汁[J].茶,1974,(1]):62-65.
    [18]戴前颖.绿茶饮料加工中沉淀和褐变的形成机理及解决方案[D].安徽农业大学,2007.
    [19]Huafu Wang,Keith Helliwell.Determination of flavonols in green and black tea leaves and green tea infusions by high performance liquid chromatography[J].Food Reach International,2001,34:223-225
    [20]罗海辉,茶叶中黄酮类物质的色谱分析及相关性研究[D].湖南农业大学,2007.
    [21]杨贤强,王岳飞,陈留记,等.茶多酚化学[M].上海:科学技术出版社,2003.
    [22]Harbone J B.Williams C A.Advvances in flavonoid research since 1992[J].Phytochemistry 2000,55:481
    [23]Andrews Schieber,et al.Determination of pHenolic acid flavonoids of apple and pear by high-performance liquid chromatography[J].Chromatogr.A,2001,910:26(5):5-273.
    [24]Samir A.Ross,David S.Ziska,Ke Zhao,et al.Variance of common flavonoids by brand of grapefruite juice[J].Fitoterapia,2000,71:14-160.
    [25]Harborne,J B,Wliilams,C A.Anthocyanins and other flavonoids[J].Natural Product Reports,2001, 18:310-320.
    [26]黄怀生,郑红发,袁英芳等.优质绿茶生产的理论与实践III茶树生物学与生物化学研究[J].茶叶通讯,2008,35(4):21-26.
    [27]钟映富,胡翔.提高重庆绿茶色泽品质的主要措施[J].茶叶,2003,31(3):47-50.
    [28]潘玉华,吴礼辉.青茶茶树品种制名优绿茶试验[J].中国茶叶,2000,(4):13.
    [29]黄建琴,丁勇.茶树良种名优绿茶适制性的研究[J].茶业通报.1999,(1):26-27.
    [30]周跃斌,蔡利娅,罗理勇等.不同茶树品种名优绿茶品质比较研究[J].湖南农业大学学报,2006,32(3):320-322.
    [31]徐步成.绿茶脂溶性色素分析与新型高桥银峰外形色泽形成机理研究[D].湖南农业大学,2007.
    [32]沈培和.改善名优绿茶色香味的措施[J].中国茶叶,2001,2:15-16.
    [33]齐桂年,谢建国,吴永刚等.微波在茶叶加工中对绿茶品质影响的初探[J].福建茶叶,2004(3):3-4.
    [34]王兴平,张弛,钟建国等.夏秋名优茶加工技术研究[J].湖北民族学院学报,1999,17(2):41-43.
    [35]张鹰,祖峰,周才琼.提高秋名茶品质的生产工艺流程初探[J].蚕桑茶叶通讯,2005(2):26-28.
    [36]于从田,刘勤晋.粗老茶杀青叶去涩保绿研究[J].西南农业大学学报,1997,10:499-502.
    [37]金寿珍,江和源,刘栩.名优绿茶护绿技术研究[J].中国茶叶,2005,5:32-33.
    [38]钟应富,李中林,袁林颍等.杀青方式对秋季绿名茶品质的影响[J],西南农业学报,2008,21(5):1385-1387.
    [39]童宗寿.筛网制茶法[J].中国茶叶加工,1998,(4):16-17
    [40]刘湘鸣.关于提高我省绿茶品质的技术途径[J].茶叶通讯,2005,32(3):33.
    [41]方世辉.机制名优绿茶常见品质缺陷的成因[J].中国茶叶加工,1999,(4):25-27.
    [42]钟应富,李中林,袁林颍等.条形绿名茶揉捻技术对其色泽品质的影响[J],西南园艺,2005,33(4):12-13.
    [43]于从田,刘勤晋.粗老茶杀青叶去涩保绿研究[J].西南农业大学学报,1997,10:499-502.
    [44]蔡健荣.利用计算机视觉定量描述茶叶色泽[J].农业机械学报,2000,3(14):67-70.
    [45]龚加顺,刘佩瑛,刘勤晋等.茶饮料品质相关成分的近红外线光谱技术分析[J].食品科学.2004,25(2):135-140.
    [46]王文杰.电脑读取茶叶色泽参数的方法研究[J].中国茶叶加工,2003(4):36-41.
    [47]陆松侯,施兆鹏.茶叶审评与检验[M].北京:中国农业出版社,2003,22-31.
    [48]刘仲华.茶叶色泽理化检测方法研究进展[J].福建茶叶,1988(4):24-27.
    [49]严俊,林刚.测色技术在茶叶色泽及品质评价中的应用研究(二)茶叶色泽的测定[J].茶叶通 报,1995,17(2):1-3.
    [50]王文杰.茶叶色泽研究概况及其前景[J].福建茶叶,2003(4):31-32.
    [51]陆建良,梁月荣.茶汤色差与茶叶感官品质相关性研究[J].茶叶科学,2002,22(1):57-61.
    [52]李立祥,梅玉,常珊等.绿茶汤色分析[J].食品与发酵工业,2005,31(10):123-126.
    [53]王艳萍.真空冷冻干燥技术原理简介[J].河南省食品学会,2008,114-116.
    [54]孔凡真.真空冻干食品前景广阔[J].农业与技术,2002,22(6):150-152.
    [55]孔凡真.市场前景广阔的真空冻干食品[J].实用技术市场,2001,(11):16-17.
    [56]黄伟东,方桦.速溶茶的真空冷冻干燥技术[J].冷饮与速冻食品工业,2001,7(2):21-23.
    [57]蔡雅娟.茶叶的干燥技术研究进展[J].福建茶叶,2005(3):22-23.
    [58]叶乃兴,杨如兴,杨广,等.冷冻干燥技术在乌龙茶加工中的初步应用[J].福建农业科技,2004,(6):40.
    [59]叶乃兴,杨如兴,杨广,等.真空冷冻干燥对乌龙茶想起品质的影响[J].茶叶科学,2006,26(3):181-185.
    [60]文静,王守生.新型绿碎茶初制工艺及其只差品质分析[J].福建茶叶,2008,(1).
    [61]顾谦,陆锦时,叶存宝.茶叶化学[M].合肥:中国科技大学出版社,2005,8-160.
    [62]严俊,林刚.测色技术在茶叶色泽及品质评价中的应用研究(一)表色系的选择[J].茶叶通报,1995,17(1):7-9.
    [63]何书美,刘敬兰.茶叶中总黄酮含量测定方法的研究[J].分析化学,2007,35(9):1365-1368.
    [64]成浩,王丽鸳,周健,等.基于化学指纹图谱的扁形茶产地判别分析研究[J].茶叶科学,2008,28(2):83-88.
    [65]郭桂义,刘黎,胡强,等.春季不同时期信阳毛尖茶的化学成分和品质的比较研究[J].食品科技,2007,(9):141-142.
    [66]潘科,何萍,郑文佳.6CW-6E型多管微波杀青干燥机杀青参数研究[J].茶叶科学技术,2010,(2):13-18.

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