四川南路边茶康砖主要工序品质成分含量的研究

对四川南路边茶康砖主要工序品质成分含量进行了研究。结果表明，渥堆工序段咖啡碱、茶多酚和水浸出物含量减少，儿茶素、氨基酸含量略有增加；蒸压工序段咖啡碱含量略有增加，其它成分均减少，氨基酸含量减少达50%以上。     

红茶发酵影响因素及品质调控技术研究进展

红茶是我国主要的消费茶类之一,其加工步骤为萎凋、揉捻、发酵和干燥,其中发酵是红茶品质特征形成的关键环节。关于红茶发酵过程中影响因素及品质调控技术,已有文献表明,多酚类物质含量及组成比例、酶种类及其活性、温度、湿度、pH,以及发酵过程中微生物等内部及环境因素均会影响红茶品质特征化合物的形成,从而影响其品质。目前常用的品质调控技术主要包括新发酵技术、冷冻萎凋技术、外源酶技术以及光质。未来研究重点将是优化红茶适制品种培育、环境因子间的交互作用机制、微生物对红茶发酵品质的影响机制和加工设备智能化等方面,因此本文通过对红茶发酵影响因素及品质调控技术的研究进展进行综述,以期为提升红茶的滋味品质和推进红茶新研究进展提供借鉴与参考。     

茶叶中滴滴涕农药残留质控样品的制备与评价

目的建立有机氯类农药残留质控样品的制备方法并对制备技术进行评价。方法以茶叶为基质,滴滴涕为目标物,采用基质添加的方式制备质控样品。采用气相色谱-电子捕获检测器法(gas chromatography-electron capture detector,GC-ECD)对质控样品中目标物含量进行测定。通过随机抽样测定以评估样品的均匀性,通过观察样品在12个月内目标物检测结果变化以评估样品的稳定性,通过10家实验室对质控样品协同定值并进行不确定度评估。结果本研究确定了质控样品中滴滴涕的标示值及不确定度。该方法制备的滴滴涕质控样品均匀性和稳定性良好。质控样品便于贮藏、运输且在常温下能够稳定保存12个月。结论本研究确立了茶叶中滴滴涕质控样品研究的可行性,所建立的制备技术可以确保质控样品定值结果的准确性,为有机氯类农药残留质控样品制备方法的开发提供技术支持。     

A model for predicting black tea quality from the carotenoid and chlorophyll composition of fresh green tea leaf

The plant pigment (carotenoid and chlorophyll) composition of fresh green leaf of tea for a selection of clones was studied in relation to the quality of black tea produced from processing the same green leaf. The plant pigment composition of the green leaf for nine Kenyan clones was monitored by HPLC at 450 nm. Using discriminant analysis it was shown that clones could be distinguished from one another on the basis of their green leaf plant pigment composition. Using step-wise multiple regression analysis, a linear relationship was established between the levels of six green leaf plant pigments peak 5 (neochrome), peak 17 and 18 (isomers of lutein and/or lutein epoxide), peak 23 (chlorophyll b type compound), peak 26 (aurochrome) and peak 28 (β-carotene)) and the quality of the manufactured black tea for the selected clones as assessed by tea tasters' evaluations. The model had an adjusted R-square value of 0.912 and was significant at P≤ 0.05. The value of the relationship as a means of predicting black tea quality is discussed.     

Enzymatic treatment to improve the quality of black tea extracts

Enzymatic extraction was investigated to improve the quality of black tea extracts with pretreatment of pectinase and tannase independently, successively and simultaneously. Pectinase improved the extractable-solids-yield (ESY) up to 11.5%, without much of an improvement in polyphenols recovery, while tannase pre-treatment showed a significant improvement in polyphenols recovery (14.3%) along with an 11.1% improvement in ESY. Among the four treatments, tannase-alone treatment showed the maximum improvement in tea quality, with higher polyphenols-in-extracted solids. Treatments involving tannase resulted in the significant release of gallic acid, due to its hydrolytic activity, leading to greater solubility besides favourably improving TF/TR ratio. The results suggested that employing a single enzyme, tannase, for the pre-treatment of black tea is desirable. Enzymatic extraction may be preferred over enzymatic clarification as it not only displayed reduction in tea cream and turbidity but also improved the recovery of polyphenols and ESY in the extract, as well as maintaining a good balance of tea quality.     

Chromium contamination in black tea and its transfer into tea brew

A survey was conducted in south India to find out the amount of chromium (Cr) present in marketable black tea. Before assessing the Cr content in black tea, the Cr content in the green shoots was assessed, in order to know the Cr contamination after completion of the manufacturing process. Samples of black tea manufactured by CTC (Crush, Tear and Curl) and Orthodox processes were collected and analysed for Cr content. The study revealed that the content of Cr was high in CTC-manufactured black tea, which involved the use of stainless steel rollers. A pilot scale experiment was carried out, using newly sharpened rollers, and the black tea samples prepared were analysed for Cr content. A similar study was carried out in a commercial factory and samples analysed for Cr for one month. The study confirmed that Cr content was positively correlated to the sharpening of CTC rollers used for manufacturing.     

近红外光谱技术在茶叶品质评价中的研究与应用

介绍了近红外光谱技术的原理及其在品质评价方面的研究进展,着重阐述了该技术在茶叶品质评价中的研究概况以及存在的问题,并对该技术在茶叶品质评价中的应用前景进行了分析。     

Metabolomics in quality formation and characterisation of tea products: a review

Tea is one of the biggest categories of modern non-alcoholic beverages with health benefits. Through different processes, tea products are divided into six main types: green tea, yellow tea, white tea, oolong tea, black tea and dark tea. Metabolomics is helpful for the comprehensive, accurate and rapid determination of tea metabolites in different types of tea products and tea processing materials. It has been widely applied in studying the relationship of tea metabolites and its quality. Therefore, it is necessary to summarise the application of metabolomics in tea. In this review, we described and summarised (1) the main metabolites of six types of tea and their implications on tea quality with emphasis on the content differences in the main metabolites in different types of tea; (2) the research on optimising the key processing steps of six types of tea based on metabolomics and the discussion of various new strategies for effectively improving their quality and (3) the advanced approach to characterise and distinguish different grades of tea products via metabolomics. The current review offers guidance for the improvement of tea quality by metabolomics and its potential challenges.     

四川黑茶活性成分、抗氧化能力及品质评价

目的：以26种市售四川黑茶（S1~S26）为材料,分析茶多酚单体、咖啡碱（CAF）、总多酚（TPC）和总黄酮（TFC）含量,并考察其体外抗氧化活性。方法：采用梯度洗脱分析茶多酚单体、咖啡碱含量,分别采用福林酚法和化学分析法分析总多酚和总黄酮含量,并以DPPH自由基和ABTS自由基清除能力评价抗氧化活性。结果：黑茶中没食子酸（GA）、没食子儿茶素（GC）、表没食子儿茶素（EGC）、儿茶素（C）、表儿茶素（EC）、表没食子儿茶素没食子酸酯（EGCG）、没食子儿茶素没食子酸酯（GCG）、表没食子儿茶素（ECG）、儿茶素没食子酸酯（CG）、咖啡碱（CAF）、总酚酸（TPC）、总黄酮（TFC）含量分别为0.26~19.64,0.72~4.73,0.00~20.28,0.00~0.95,0.00~6.06,0.32~9.44,0.62~63.12,0.29~17.08,0.21~1.81,9.53~44.43,20.96~279.05,7.92~17.49 mg/g。ABTS自由基清除力以水溶性维生素E当量计算为33.49~232.87 mg/g,DPPH自由基清除力以水溶性维生素E当量计算为45.26~237.59 mg/g。相关性分析表明DPPH自由基清除能力与10个单体化合物以及总多酚和总黄酮含量均存在显著（P＜0.05）或极显著（P＜0.01）的正相关;ABTS自由基清除能力与GC、GA、CAF含量存在极显著正相关（P＜0.01）,与TPC和TFC含量存在显著正相关（P＜0.05）。主成分分析表明EGCG、C、TPC 3个成分累计贡献率为87.566%。结论：S16、S23、S19 3种黑茶得分较高,品质较好。     

三种砖茶品质生化成分的研究

通过比较三种砖茶中各种生化成分含量的差异,分析了不同加工工艺对砖茶生化成分以及成茶品质风味的影响。实验结果表明,黑砖茶的水浸出物、茶多酚、咖啡碱、游离氨基酸及三种色素的含量均为最高,茯砖茶次之,青砖茶最低,而可溶性糖的含量是黑砖茶最低,青砖茶最高。三种砖茶生化成分的差异主要是由不同的加工工艺造成的,茯砖茶有独特的"发花"工序,其品质表现为有菌花香,滋味醇和;黑砖茶的原料较嫩,加工过程比较简单,内含成分高,滋味表现为纯厚微涩;青砖茶的原料最为粗老,自然发酵时间长,可溶性糖含量高,其品质表现为香气纯正,滋味甘甜。     

白茶馒头的配方优化及品质评价

目的 优化白茶馒头的配方并评价其品质。方法 在传统馒头制作的基础上, 通过单因素试验和正交试验考察酵母、白砂糖和茶叶添加量3个因素对馒头品质的影响。结果 白茶馒头的最佳配方为: 酵母1.5 g、白砂糖16.0 g、白茶18.0 g, 经蒸制得白茶馒头的感官评分为95.7, 颜色鲜艳均匀有光泽、茶味清甜醇爽、表面光滑, 弹性适中、咀嚼时爽口不粘牙, 没有异味和苦味, 外观平滑, 表面色泽均匀, 具有白茶独特的香味; 且该白茶馒头样品中含有氨基酸及其衍生物、糖及醇类、维生素、有机酸、游离脂肪酸、核苷酸及其衍生物、溶血磷脂酰胆碱、溶血磷脂酰乙醇胺、甘油酯等初生代谢物。结论 该白茶馒头的风味独特、营养丰富, 具有极大的开发价值, 可为茶叶馒头和风味食品的研发提供参考。     

食品感官评价技术在茶叶品质评价中的 应用研究进展

食品感官评价是用于唤起、测量、分析和解释通过视觉、嗅觉、味觉、触觉以及听觉而感知到的食品及其他物质的特征或者性质的一种科学方法,已经建立了科学的评价程序与方法,已广泛应用于产品的感官特征评价及产品鉴别、产品开发、市场调查等方面的研究。我国茶叶品类多样,产品风味独具特色。我国茶叶感官质量评价方法仍然是定级评价,采用食品感官评价技术建立更客观、更有效的产品感官质量评价体系十分必要。本文介绍了食品感官评价定义、方法及其在茶叶风味化合物研究,对典型茶叶(绿茶、红茶和乌龙茶)感官描述分析、典型茶叶感官术语及参考物、茶叶及茶产品消费者测试中的研究进展进行了综述,并提出了食品感官评价技术在茶叶感官品质评价研究发展方向。     

酶对改善茶汤萃取品质的研究

在茶饮料生产过程中,使用酶可改善茶汤品质。结果表明,纤维素酶能有效提高红茶茶汤可溶性固形物含量和茶多酚含量。茶叶粒径也会对加酶茶汤的萃取品质产生很大影响,当茶叶平均粒径小于105μm时,茶汤内在品质会得到明显改善。     

Phenolic composition of black tea liquors as a means of predicting price and country of origin

Seventy-seven black teas from seven countries were analysed by HPLC. The relative levels of the 11 most prominent peaks detected at 380 nm were determined. The teas were priced or scored by professional tea tasters. Statistical analysis of the HPLC results, with principal component analysis (PCA) and canonical variate analysis (CVA), highlighted the characteristic differences in phenolic constituent levels which contributed most powerfully to the discrimination between countries. Multiple regression was used to investigate the relationship between price (or score) and phenolic constituent level. Certain phenolic constituents seem to be important in determining quality but further work is recommended to ensure the significance of the observed trends.     

红茶发酵过程中品质评价技术研究进展

发酵是红茶特征品质形成的关键环节,快速准确地评判红茶发酵度,对于红茶加工至关重要。文章综述了近年来人工感官评价技术、生化成分检测技术、智能仿生技术、数据融合技术以及智能仿生设备等评价技术在红茶发酵品质评价中的应用现状,并对智能仿生技术在未来红茶发酵评价中的应用趋势进行了展望。     

3种新式茉莉花茶饮基底茶品质分析

目的:探究新式茉莉花茶饮基底茶的品质特点。方法:以福建、云南、四川3地茶坯窨制而成的3种新式茉莉花茶茶饮基底茶(福建香毫、云南毛尖、四川香茗)为研究对象，利用电子舌、固相微萃取—气相色谱质谱技术，结合理化检测和感官审评，从主要化学成分以及滋味、香气等品质进行分析。结果:3种基底茶的水浸出物含量为49.40%～51.40%,茶多酚含量为18.00%～23.20%,咖啡碱含量为3.20%～4.30%,游离氨基酸含量为3.32%～3.50%。除游离氨基酸外，云南毛尖的主要生化成分含量、酚氨比及16种氨基酸含量均高于其他两种。云南毛尖茶汤的涩味、咸味及丰富度响应值最大，但甜度响应值最低，茶汤浓厚；福建香毫涩味、咸味响应值最小，但水浸出物含量高，茶汤浓醇。香气组分中酯类相对含量最高，其次是醇类和烯烃类化合物；3种基底茶的香气品质由高到低为福建香毫、云南毛尖、四川香茗，均属于中等。结论:3种基底茶内含物质丰富，但香气质量有待提高。     

茶渣资源的开发与利用——茶渣中茶叶蛋白的酶法提取和酶法水解

关于茶叶蛋白的研究及其开发利用,目前研究得较多的主要为茶叶蛋白的工业化提取.本文在现有茶渣中茶叶蛋白提取工艺的基础上,采用新的复合酶酶法提取工艺(固液比1:35,复合酶B加量0.5％,碱浓度0.1N,温度50℃(2h)→90℃(2h)),使蛋白提取率和蛋白纯度都有了较大的提高,分别可达到85.3％和82.4％.并对所提取的茶叶蛋白的酶法水解工艺进行了研究,通过试验,确定了酶法水解茶叶蛋白的最佳酶解工艺条件为:温度50℃、pH9.0、底物浓度10％、酶添加量2％、水解时间4hr;在此条件下,茶叶蛋白的水解度可达74.0％.水解产物中含有大量的小分子蛋白质和多肽,多肽含量可达到40.85％.本研究从根本上解决了茶渣资源开发与利用的主要限制性因素——茶叶蛋白高抗性,从而在一定程度上加大了茶渣资源应用的广泛性和可行性.     

玫瑰花、玫瑰茄、滇红茶、绿茶复合饮料的研制

以玫瑰花、红茶、绿茶、玫瑰茄为主要原料研制复合饮料。采用L2(556)正交试验和感观评定的方法确定了饮料的最佳配方及加工工艺。试验表明添加红茶4g·L-1、绿茶g·L-1、玫瑰花8g·L-1、玫瑰茄10g·L-1、白糖120g·L-1、柠檬酸0.2g·L-1,饮料感观品质最好。     

花生蛋白奶茶的开发研制

以红茶、花生蛋白和脱脂奶粉等为主要原料，通过对茶汤的浸提试验、花生蛋白的酶解试验、产品配方调制试验以及稳定剂的配比试验研究，最终确定了花生蛋白奶茶的最佳产品配方：红茶茶汤50％，花生蛋白酶解液20％，蔗糖9％，脱脂奶粉1．5％，蔗糖脂肪酸酯0．15％，分子蒸馏单甘酯0．05％，卡拉胶0．025％，柠檬酸钠0．03％，焦磷酸钠0．05％。     

贵州玫瑰花茶的氨基酸组成及其品质综合评价

目的 检测贵州玫瑰花茶的氨基酸含量,分析其组成特征对其品质进行综合评价。方法 参照GB 5009.124—2016《食品安全国家标准 食品中氨基酸的测定》,收集贵州5个产区（镇远、毕节七星关区、沿河、开阳、凤冈）不同品种及不同开放程度共12个玫瑰花茶,利用氨基酸自动分析仪测定其氨基酸含量,通过主成分分析和聚类分析等方法比较玫瑰花茶品质。结果 贵州各产区玫瑰花茶均含16种氨基酸,其中均为天冬氨酸含量最高,平均氨基酸总量在5.96~13.27 g/100 g之间,必需氨基酸、儿童必需氨基酸、药用氨基酸含量分别为2.05~4.16 g/100 g、0.43~0.96 g/100 g、3.85~9.05 g/100 g;通过主成分分析提取了2个主成分,累计方差贡献率为86.072%,能较好地反映氨基酸的综合信息,结果表明5-GZ,3-GZ和1-GZ氨基酸品质最佳;聚类分析将12个玫瑰花茶分为4类,表明这12个玫瑰花茶氨基酸品质有明显差异。结论 贵州各产区玫瑰花茶氨基酸含量丰富,通过综合评价氨基酸品质最好为镇远产丰花花蕾茶。