机械超微粉碎与不同粒度常规粉碎对红茶理化特性的影响

为探究机械超微粉碎对茶叶物性及功能成分浸出特性的影响,该文通过超微粉碎和常规粉碎2种方法制备超微红茶粉和4种粒度的粗粉红茶粉,研究了5种茶粉的粒度分布、微观形貌、比表面积、结晶度、表面氧碳元素比、中红外图谱和功能成分的浸出特性。结果表明:常规粉碎不同粒度茶粉间差异较小,而超微粉碎较大程度地改变了茶叶的物料性质。超微粉碎后,茶粉粒度减小至微米级,比表面积增大,茶粉的结晶度降低,表面暴露的纤维素和半纤维素相对含量增多,而中红外谱图显示超微粉碎茶粉的官能团结构并没有改变。沸水浸提过程中茶多酚、咖啡因、可溶性糖和水浸出物的溶出结果表明:5种茶粉功能成分的浸出量都随时间的增加而增加,经过一段时间后达到平衡。在达到浸出平衡时,不同粒度茶粉的茶多酚和咖啡因含量差异不显著,超微茶粉的可溶性糖含量为4种粗粉的2倍左右,水浸出物比粗粉茶粉提高10%以上。上述研究结果表明:超微粉碎能够有效减小茶粉的粒度,破坏植物的细胞壁结构,使内部成分暴露于表面,此外,组织结构和细胞壁的破坏使不溶的纤维成分转化成可溶性成分,可溶性糖和水浸出物显著增多,超微粉碎能够在一定程度上提高茶粉的有效利用率。     

不同工艺制法对茶叶风味品质化学轮廓的影响

为探明不同工艺制法对茶叶风味品质化学轮廓的影响,本研究对福建4种茶类(绿茶、白茶、红茶和乌龙茶)及其鲜叶原料中的主要滋味和香气品质成分进行了检测分析和可视化模式识别。结果表明,基于茶叶主要滋味品质成分的主成分分析(PCA)可将全部供试茶样划分成3种类群:Ⅰ型:绿茶、白茶和一芽二、三叶鲜叶样;Ⅱ型:乌龙茶和中、小开面2~4叶鲜叶样;Ⅲ型:红茶。采用偏最小二乘增强判别分析(PLS-EDA)可进一步放大不同类群茶样的组间差异,乌龙茶及其鲜叶原料有较高含量的水溶性碳水化合物(WSCs),而红茶中多酚类(TPs)和表没食子基儿茶素没食子酸酯(EGCG)含量相对较低;(茶多酚×游离氨基酸)含量二维散点视图可作为茶叶分类识别的一种重要判别工具。4种茶类以乌龙茶的香型种类最为丰富,绿茶与鲜叶原料的香气组成化学模式较为接近,白茶与红茶香气组成在种类和数量上存在一定的相似特征。2,6-二叔丁基对甲苯酚、苯乙腈、4-乙基苯甲酸-2-苯基乙酯类似物、反式-橙花叔醇、α-法呢烯、吲哚等可视为乌龙茶有别于其他3种茶类(绿茶、白茶和红茶)的主要特征香气成分。本研究结果为茶叶化学分类及其工艺品质的目标控制提供了参考依据。     

自动化加工生产线改善机采绿茶理化品质研究

以茶树机采鲜叶为原料,选配、改装和组建了茶叶加工自动化生产线,并跟踪加工工序中茶坯理化成分的动态变化,以同一原料所制的传统炒青工艺为对照,比较新设备和新工艺对机采卷曲形绿茶色泽和品质成分的影响。结果发现:新的生产线在杀青、二青、做形和提香等关键工序中,集成应用了电磁加热耦合热风、热管余热回收和流化床干燥技术,提高了茶叶的滋味和色泽品质,所制卷曲形绿茶的感官得分比传统炒青绿茶高2分,酚氨比相对较低(P0.05),干茶的色相值、茶汤、叶底的亮度和色相值相对更好(P0.01);相比传统单机加工设备,该生产线可日均生产绿茶1 750 kg,产能提高了37.5%,能耗成本为4.6～4.8元/kg干茶;热效率提高100%,用工成本减少50%。机采卷曲形绿茶自动化生产线扩大了茶叶加工产能,减轻了劳动强度,提高了卷曲形绿茶品质,为实际生产提供了指导。     

球磨法和均质法改善薇菜粉物化及功能性质

为研究不同超微粉碎方法对薇菜粉体物性、主要成分含量及活性物质保留的影响,该文以行星球磨法、高压均质法对薇菜进行超微粉碎,分别研究薇菜超微粉体的粒径、休止角、粉体膨胀力、持水力、持油力等物理性质;检测其总蛋白、粗脂肪、多糖、总黄酮、总多酚等主要成分含量;通过薇菜超微粉提取液抑制?-葡萄糖苷酶及?-淀粉酶的能力,初步探究两种薇菜超微粉的降血糖活性。结果表明:对比常规粉碎方法,经行星球磨法和高压均质法处理后,粉体粒径分别减小1/48倍和1/65倍,粉体休止角增加,粉体膨胀力降低,高压均质和行星球磨法的持水力分别是常规粉碎法的2.43倍和2.44倍、持油力分别是常规粉碎法的1.99倍和1.52倍;几种主要成分高压均质法、行星球磨干法显著高于常规粉碎;2种超微粉提取物的?-葡萄糖苷酶和?-淀粉酶抑制率均优于常规粉碎提取物。上述结果表明:2种超微粉碎方法均有改善粉体物性作用,高压均质法对于薇菜粉体纤维组织破坏更加完全,主要成分易溶出,微粉处理促进了粉体的降血糖生理作用的发挥。     

微波远红外耦合杀青工艺对绿茶品质的影响

为研究微波远红外耦合杀青工艺对绿茶品质的影响,试验分析了杀青时间、杀青功率和投叶量等因素对绿茶香气、滋味品质的影响,通过L9(34)正交试验设计,优化了绿茶微波远红外耦合杀青工艺,并与其他杀青方式进行了比较,结果表明：较佳的耦合杀青工艺为杀青功率微波10 kW +远红外6 kW,投叶量0.5 kg/min,杀青时间先微波1.5 min+后远红外1.5 min。此时杀青的茶叶香气滋味最好,感官品质总分达到91.40,茶多酚、儿茶素、咖啡碱、氨基酸、可溶性糖和芳香油质量分数分别达到17.24%、12.62%、3.10%、3.72%、4.64%、15.40×10-2 mg/g,香气滋味品质好于其他杀青方式,杀青时间是传统杀青的1/4～1/3,能耗成本是传统杀青的1/3～1/2。该杀青工艺克服了单纯使用微波杀青的不足,为绿茶加工生产提供参考。     

绿茶电磁滚筒-热风耦合杀青工艺参数优化

为探究电磁滚筒-热风耦合杀青对绿茶品质的影响,该文运用响应面设计,以杀青样生化成分含量和成茶感官品质为指标,对电磁滚筒-热风耦合杀青工艺参数(热风温度、热风风量、筒体前段温度等)进行优化,并与电热管滚筒杀青、微波杀青、热风杀青、电磁内热滚筒杀青等进行比较,结果表明:当投叶量为150 kg/h时,电磁滚筒-热风耦合杀青的最佳参数组合为热风温度104℃,热风风机转速920 r/min,筒体前段温度270℃;此工艺下所制成茶香气、滋味、色泽等品质最好,感官总分达到91.0,较其他杀青方式要高2.7~4.0分,杀青叶茶多酚、氨基酸、可溶性糖、儿茶素、咖啡碱和黄酮的质量分数分别为13.849%、2.057%、8.412%、9.724%、2.172%、1.336%,品质物质加权值达7.018%;该杀青工艺能耗成本较电热管滚筒杀青减少1/2,热能利用率达45%~55%,克服了传统滚筒杀青的不足,可为绿茶生产提供指导。     

辐照杀菌对绿茶品质的影响

本文研究了辐照对绿茶主要品质成分、重金属、农药残留及感官品质变化的影响。结果表明:辐照对茶叶中粗蛋白、茶多酚、咖啡碱、重金属元素无显著影响,可溶性糖、氨基酸有一定的影响。氯氰菊酯含量随辐照剂量的增加呈下降趋势,5kGy以下剂量辐照茶叶对绿茶色泽、汤色、滋味、香气无明显影响。根据品质因素综合分析确定,辐照茶叶的适宜剂量为3~5kGy。     

不同杀青方法对绿茶品质的影响

杀青作业是提高绿茶加工品质的关键工序,为了提高茶叶加工品质,采用微波、热风、蒸汽、锅炒和蒸汽-热风组合等不同杀青方法对加工后绿茶的感官品质和茶叶内含成分品质特性进行了试验分析,结果表明：微波输出功率 10 kW、时间2.5 min、杀青叶温室75℃,杀青后茶叶的外形色泽、汤色、叶底表现较好,只有香气、滋味欠佳,咖啡碱、茶多酚、维生素C和叶绿素含量最高,分别是2.70%、34.40%、3.335×10-3 mg/g和2.24 mg/g,时间是传统杀青的1/4～1/3,能耗成本是传统杀青的1/3。蒸汽-热风组合杀青时间为6 min（蒸汽和热风各处理3 min）、叶温80℃杀青的茶叶香气最好,氨基酸保留量达到3.48%,感官品质总分达到90.75分。     

基于Elastic Net特征变量选择的黄山毛峰茶等级评价

为简化茶叶化学检测分析过程,实现茶叶高精度等级评价,该研究以黄山毛峰茶为研究对象,结合茶叶中茶多酚、儿茶素、咖啡碱、没食子酸及氨基酸成分检测,提出基于Elastic Net特征变量选择的茶叶等级评价方法,建立基于特征成分的黄山毛峰茶等级评价模型。试验选取6个不同等级共96个黄山毛峰茶叶样品,并分析了全部样品的19个成分,通过ElasticNet选取了9个特征成分(没食子酸、表儿茶素没食子酸酯、儿茶素、表儿茶素、没食子酸儿茶素没食子酸酯、表没食子儿茶素、谷氨酸、精氨酸和儿茶素苦涩味指数)建立等级评价模型,并与主成分分析(Principal Components Analysis, PCA)进行对比。100次蒙特卡罗试验结果表明,相比于PCA预测集准确率平均值为70.79%,基于Elastic Net特征变量选择的黄山毛峰茶等级评价准确率更高为78.72%。在此基础上,构建Elastic Net特征变量雷达图,实现黄山毛峰茶等级多变量综合评价可视化。研究结果表明所提方法可有效选择茶叶特征成分,提高黄山毛峰茶等级评价准确率,为茶叶高精度等级评价提供参考。     

茶园施肥模式对茶叶黄酮类及糖苷类代谢物含量的影响

【目的】研究施肥模式对茶叶生化成分含量和黄酮类及糖苷类代谢物累积的影响,为实现茶叶优质高产提供科学依据。【方法】田间试验设在四川茶树种植典型区域—雅安,试验连续进行了3年,设置不施肥(CK)、常量化肥(N 585 kg/hm2,TF)、有机肥替代25%化肥氮(OF)、减施25%氮肥(SF) 4个处理。分析了不同处理茶叶主要品质成分含量,并基于非靶向代谢组学检测结果分析了黄酮类及糖苷类代谢物累积差异。【结果】与C K处理相比,T F、 O F、 S F处理茶氨酸、游离氨基酸含量分别提高了7.2 2%～1 3.4 0%、23.15%～25.50%,可溶性糖和茶多酚含量分别降低了8.17%～13.86%、6.08%～11.49%,表儿茶素、表没食子儿茶素、芸香苷等10种代谢物累积水平显著下降。与TF处理相比,SF处理茶氨酸、咖啡碱和水浸出物含量分别降低了5.45%、5.97%、8.91%,茶多酚、可溶性糖、游离氨基酸含量和酚氨比无显著差异;芍药素-3-O-葡萄糖苷、肉桂萜醇C1-19-葡萄糖苷、查耳酮樱花素等7种代谢物累积水平显著降低,川陈皮素、牡荆素-4’-O-α-L-吡喃鼠李糖苷、(S)...     

树冠微域环境对茶树碳氮代谢的影响

【目的】树冠微域环境对植物的生长有着显著影响,改善植物树冠环境可提升收获对象的品质。因此茶树的生长特别是其碳氮代谢及茶叶品质可能会受到树冠微域环境影响,本文拟通过覆盖遮荫的方式人为改变茶树树冠微域环境,以探明树冠微域环境对茶树碳氮代谢等的影响。【方法】采用田间小区试验,通过在茶树树冠面上分别覆盖光热透过性能不同的三种遮荫材料,人为改变茶树树冠面的微域环境,以不覆盖为对照,比较不同树冠微域环境条件下树冠面空气温度、空气湿度、光照等环境因子的变化及光合速率等的差异,并通过氨基酸组分分析及高效液相色谱等方法对不同季节茶树新梢中碳氮初级代谢产物进行分析,以比较树冠微域环境变化对茶树碳氮代谢及茶鲜叶品质等的影响。【结果】茶树树冠面经三种光热透过性能不同的遮阳网在蓬面直接覆盖后,茶树新梢的生长小环境及碳氮代谢均发生了变化: 1）树冠面的光照强度、空气温度及叶片温度均得到了不同程度的降低,空气相对湿度得到了不同程度的提高。其中覆盖隔热网的降温效果最好,降温幅度最高可达3.1℃;覆盖银色网在早晚有较好的降温效果,降温幅度可达1.6℃,但在12时、14时和16时未有明显的降温效果。而覆盖黑网后早晨的树冠面空气温度与叶片温度却显著高于其他各处理,且随着外界温度的升高,黑网下的两种温度与不覆盖比表现出了波动现象。2）茶树被覆盖后,其净光合速率表现出显著的降低趋势,其中黑网覆盖处理与不覆盖处理均在中午12点左右出现一个低谷,出现了午睡现象,而银色网与隔热网覆盖处理没有表现出午睡现象;覆盖后茶树叶片胞间CO2浓度较不覆盖表现出升高趋势,其中以隔热网处理为最高。3）在高温强光季节对茶树进行适度遮荫覆盖,能在一定程度上促进茶树氮代谢,减弱茶树碳代谢,改善各季茶树新梢的品质。主要表现为茶新梢的叶绿素含量、氮磷钾等养分含量、游离氨基酸总量显著增加;氨基酸组分如茶氨酸、谷氨酸、天冬氨酸等也均表现出显著增加趋势;茶新梢中总碳含量及茶多酚等碳水化合物含量降低;总碳、C/N、茶多酚含量等显著降低,儿茶素组分降低但儿茶素品质指数增加、苦涩味指数降低;三种茶树微域环境中,隔热网覆盖的树冠环境对茶叶品质提升方面效果最明显。4）与不覆盖相比,茶树新梢产量表现出了降低的趋势。【结论】通过遮荫覆盖等方式调控茶树树冠微域环境会影响茶树碳氮代谢等生理活动、提高茶鲜叶品质,但茶鲜叶的产量表现出降低的趋势。     

Effect of selenium on preservation quality of green tea during autumn tea-processing season

Selenium-enriched green tea leaves were prepared by foliar applications of selenium-amended fertilizer during autumn season. The influence of selenium (Se) on preservation quality of tea during 4-month storage was determined. The results showed that the Se and vitamin C contents of green tea were significantly increased by selenium spraying during the autumn tea-producing season. The vitamin C content of Se-enriched green tea was higher and its decline was significantly slower during storage compared to normal green tea. However, there was no significant difference between the contents of chlorophyll and polyphenol of Se-enriched and regular tea. During the first 60 days, the color of green tea extract in Se-enriched green tea and normal tea showed no significant difference. However, the color of green tea extract in Se-enriched green tea was more stable compared with normal tea during the storage period. The sweetness and aroma of extracts of Se-enriched green tea were also significantly higher than that of normal tea and the bitterness of extracts of Se-enriched green tea was significantly lower compared with normal tea. These results showed that selenium application can slow the reduction of tea's major component and thus improve preservation qualities of green tea.     

气流和机械碾轧超微粉碎香菇柄的效果比较

为了提高香菇副产物菇柄的附加值,应用气流粉碎和机械碾轧粉碎2种工艺分别对菇柄进行超微处理。对气流粉碎工艺中的分级机转速,机械碾轧粉碎工艺中的主机频率、风机频率等操作参数进行了单因素分析,进一步结合分段线性拟合法对2种工艺的加料速度进行了优化,分别得出了2种工艺的较适工艺条件;并对二者的粉碎效果、处理时间、能耗和出品率进行了比较。结果显示:气流粉碎的较适工艺条件为:分级机转速2 400 r/min,加料速度12 kg/h;机械碾轧粉碎的较适工艺条件为:主机频率44 Hz,风机频率42 Hz,加料速度5 kg/h。2种超微粉碎方式都能获得10μm以下的微粉,与机械碾轧粉碎相比,气流粉碎的分级精度较高,处理时间缩短了56.43%,但出品率较低,能耗为前者的4.77倍。总体来看,机械碾轧粉碎更适合规模化生产,该研究为超微粉碎技术应用于香菇柄深加工利用提供了技术依据。     

Effects of Curtailment of Nitrogen Fertilizer on Biological Properties and Tea Leaf Yield in Acid Tea Field Soils

In Japan, the soils in tea fields are further acidified by heavy application of nitrogen fertilizer. In the long-term fertilizer application fields, available P, total carbon and nitrogen contents had the highest in the Multi-F plot, followed by the 98-D.F plot and the smallest in the 95-D.F plot. Soil enzymes activity had the highest the Multi-F plot. It was estimated that all of the enzyme activity were often corresponded with the results of the organic matter and the available P contents. The number of fungi under acidic condition had the close relation since change of these enzymes activity. It was evident that fungi were participated in carbon, nitrogen and phosphorus metabolism in acid tea field soils. It became clear that the number of fungi and enzymes activity decreased corresponding well with the available P and the organic matter contents depend on fertilization management. Moreover in case of qualities of green tea, generally difference between experimental plots and Multi-F plot were to be small. It was indicated that influence to the yields by curtailment of the amount of nitrogen fertilization was small.     

Abstracts of nippon dojo-hiryogaku zasshi,Vol. 89 (2018) No. 4

In Japan, the soils in tea fields are further acidified by heavy application of nitrogen fertilizer. In the long-term fertilizer application fields, available P, total carbon and nitrogen contents had the highest in the Multi-F plot, followed by the 98-D.F plot and the smallest in the 95-D.F plot. Soil enzymes activity had the highest the Multi-F plot. It was estimated that all of the enzyme activity were often corresponded with the results of the organic matter and the available P contents. The number of fungi under acidic condition had the close relation since change of these enzymes activity. It was evident that fungi were participated in carbon, nitrogen and phosphorus metabolism in acid tea field soils. It became clear that the number of fungi and enzymes activity decreased corresponding well with the available P and the organic matter contents depend on fertilization management. Moreover in case of qualities of green tea, generally difference between experimental plots and Multi-F plot were to be small. It was indicated that influence to the yields by curtailment of the amount of nitrogen fertilization was small.     

Degradation kinetics of catechins in green tea powder: effects of temperature and relative humidity

The stability of catechins in green tea powders is important for product shelf life and delivering health benefits. Most published kinetic studies of catechin degradation have been conducted with dilute solutions and, therefore, are limited in applicability to powder systems. In this study, spray-dried green tea extract powders were stored under various relative humidity (RH) (43-97%) and temperature (25-60 °C) conditions for up to 16 weeks. High-performance liquid chromatography (HPLC) was used to determine catechin contents. Catechin degradation kinetics were affected by RH and temperature, but temperature was the dominant factor. Kinetic models as functions of RH and temperature for the individual 2,3-cis-configured catechins (EGCG, EGC, ECG, and EC) were established. The reaction rate constants of catechin degradation also followed the Williams-Landel-Ferry (WLF) relationship. This study provides a powerful prediction approach for the shelf life of green tea powder and highlights the importance of glass transition in solid state kinetics studies.     

不同氮肥种类和用量对川西蒙山茶品质的影响

利用盆栽试验研究了尿素、硫酸铵、硝酸铵、碳酸氢铵和硝酸钙5种氮肥和用量对川西蒙山茶品质的影响。结果表明:肥料种类、肥料用量以及肥料种类与用量的交互作用对茶叶主要品质指标(可溶性糖除外)的影响极显著;不论施用何种氮肥,茶叶中的茶多酚、儿茶素和咖啡碱含量都有极显著的增加;各种氮肥用量为4g/盆时,茶多酚、儿茶素和咖啡碱含量较高;与施用其他种类的氮肥相比,尿素能极显著地提高茶叶中儿茶素和氨基酸的含量。施用硝态氮将能显著提高茶叶中硝酸盐和亚硝酸盐的含量,但随着硝态氮用量的增加,硝酸盐和亚硝酸盐的含量没有显著变化,而铵态氮和酰胺态氮对茶叶硝酸盐和亚硝酸盐含量基本没有影响。综合考虑春夏秋三季茶叶的品质,若单施一种氮肥,尿素最为合适,施用量为8g/盆左右。     

施肥模式对茶叶产量、营养累积及土壤肥力的影响

施肥是提高茶叶产量、品质、土壤质量及促进茶园可持续利用最重要的农业措施之一。为了筛选出合理的茶树施肥模式,采用连续4周年的田间定位试验方法,研究了6种不同施肥模式(不施肥、茶树配方化肥、1/2茶树配方化肥+1/2有机肥、有机肥、茶树配方化肥+豆科绿肥、1/2茶树配方化肥+1/2有机肥+豆科绿肥)对茶叶产量,茶叶中氮、磷、钾、茶多酚和水浸出物的累积量及茶园土壤肥力状况的影响。结果表明:与对照(不施肥)模式相比,其他几种不同施肥模式均在一定程度上增加了茶叶产量,促进了茶叶营养物质的累积,并提高了茶园土壤的基本肥力状况;其中,1/2茶树配方化肥+1/2有机肥+豆科绿肥的试验效果最佳,其3年茶叶总产量最高,为5 929 kg.hm?2,比对照提高106.17%;茶叶氮、磷和钾累积量最高,分别为4.962 kg.hm?2、0.48 kg.hm?2和5.966 kg.hm?2,比对照分别提高88.6%、57.41%和98.87%;茶叶茶多酚和水浸出物累积量最高,分别为23.39 kg.hm?2和119.41 kg.hm?2,比对照分别提高73.29%和85.56%;并比对照分别提高茶园土壤有机质1.29倍、全氮1.7倍、全磷2.98倍、速效氮1.59倍、速效磷34.3倍和速效钾3.3倍。1/2茶树配方化肥+1/2有机肥+豆科绿肥施肥模式值得在茶园施肥上进一步推广应用。