夏季绿茶发酵产品研制及其品质评价

夏季绿茶滋味苦涩,品质远不及春茶,为提高夏季绿茶滋味品质、拓宽资源利用,文章以夏季绿茶为原料,筛选最佳发酵菌种,研制夏季绿茶发酵产品.通过单因素与响应面优化试验,探究夏季绿茶发酵产品最佳工艺参数,并检测分析夏季绿茶发酵产品的主要生化成分及抗氧化能力.结果 表明,乳酸菌对夏季绿茶浸提液发酵作用效果较佳,优于双歧杆菌和酵母...     

风味蛋白酶对绿茶风味成分和感官品质的影响

杀青叶在不同浓度风味蛋白酶液中浸润后,经过揉捻、干燥制作成绿茶,探讨风味蛋白酶对绿茶风味成分含量和感官品质的影响。结果表明,用浓度为5.0～20.0 g/L的风味蛋白酶处理绿茶,茶叶中具有苦涩滋味的EGC、EGCG和ECG等酯型儿茶素分别下降3.35%～31.42%、4.11%～18.67%、1.05%～9.27%,具有醇和滋味的D,L-C含量增加54.51%～141.72%,儿茶素总量下降3.24%～19.03%,水浸出物和茶多酚含量均呈下降趋势,降低率分别为2.99%～5.34%、1.57%～10.58%。鲜味氨基酸和游离氨基酸总量分别下降2.33%～7.76%和2.58%～6.89%。当风味蛋白酶浓度小于10.0 g/L时,茶汤苦涩滋味明显降低,且具有一定的鲜爽度。该研究结果为利用风味蛋白酶改善夏秋季绿茶品质提供了参考。     

绿茶浓缩液风味品质的改善与重构研究

为提高茶提取物的风味品质,本文基于酶制剂现代生物技术的应用,利用外源酶或酶助剂有针对性地改善茶叶中特定成分的构成与含量,从而使茶的加工过程真正变得可调可控,实现对其风味品质的改善或重构塑造。以蒸青绿茶为原料,通过多种酶制剂及辅助手段的联用、采用有效裂解选择与定向控制综合浸提处理手段后,依次经去渣、离心、浓缩、调配、杀菌、灌装工艺过程,最终制备成独具风味的绿茶浓缩液。结果表明酶处理产品具有清香高、浓而持久、入口鲜爽、醇厚无苦涩的滋味品质特征,且茶叶有效利用率由30%增至46%,提高幅度达53.33%。在处理过程中观察到叶片组织结构被分解破坏,茶汤中肉眼可见絮状物增多,可溶性固形物含量不断增加,特别是与风味高度相关的指标还原糖和游离氨基酸总量的增长率明显高于对照组。在呈味物质方面,浓缩液中呈鲜味的氨基酸含量成倍增加,24种游离氨基酸增加了3.5倍,同时不良风味物质茶多酚及咖啡碱比例下降,而儿茶素的组成、酚氨比更趋合理,使得整体风味更加醇和、滋味饱满与协调。在香气总量和组成方面,经由酶处理后茶汤的挥发性成分总量提高了33.6%,其中芳樟醇的含量提高了75.3%。醇系化合物以及醛系化合物是浓缩汁中体现清新花香型的主要呈香物质,通过关键风味物质的有效生物降解释放与浸出调控调节,实现对茶提取物的风味品质改善与重构调控研究。     

绿茶风味发酵香肠工艺研究

在传统发酵香肠工艺的基础上,通过添加适量绿茶提取液获得了一种具有绿茶风味的发酵香肠。以重量变化和pH值为评价指标通过单因素优化试验确定了绿茶风味发酵香肠最佳肥瘦比为3:7;通过感官评价和对pH值的影响确定绿茶浸提液添加量与猪肉比为4∶6;以绿茶风味发酵香肠的感官评价结果为评价指标,通过L9(34)正交试验最终确定发酵香肠的最佳发酵工艺为乳糖添加量0.75%,接种量为4%,发酵温度为37℃,发酵时间为6h。并结合产品实际制定了绿茶风味发酵香肠的产品质量标准。     

矿石浸泡水对绿茶茶汤风味的影响

泡茶用水的离子种类及含量是影响绿茶茶汤风味品质的关键因素。为了开发泡茶专用水及其相应设备,以不同种类矿石(石英石、麦饭石、富锶滤料、弱碱滤料、高总溶解固体(TDS)滤料)为研究对象,探究矿石浸泡水对绿茶茶汤风味品质的影响。矿石浸泡水研究结果显示,石水比、浸泡时间、浸泡温度对不同种类矿石浸出规律的影响有显著差异,高TDS滤料浸泡水所含离子含量最高,石英石的溶出稳定性最佳,矿石浸泡水的最佳处理为室温下石水比1∶50,浸泡时间5 min。矿石浸泡水水质分析结果显示,5种矿石浸泡水煮沸后电导率均增大而变化幅度小于10μs/cm,pH值之间存在显著差异(P<0.05),表明矿石浸泡水电导率受温度影响小,而pH受温度影响大。矿石浸泡水所含阳离子(K⁺、Na⁺、Mg²⁺、Al³⁺、Ca²⁺)中Ca²⁺是引起矿石浸泡水电导率增大的主要阳离子,随着电导率的增加绿茶茶汤涩味显著增强,其中Ca²⁺含量与茶汤涩味强度呈极显著相关性(P<0.01)...     

改善馒头风味品质的最佳生产工艺

针对目前市场上存在的馒头口感不好、风味欠佳的现状 ,研究了以生香酵母等多种酵母搭配并用 ,以及添加酒曲酵母、啤酒花发酵醪、乳酸菌、酒类和适当的酶制剂等处理后馒头风味及品质的变化 ,提出了改善馒头质量和风味品质的最佳生产工艺条件     

云龙绿茶品质形成因素分析

影响绿茶品质形成的因子很多，本文分析了生态环境、采摘标准及加工工艺对云南名茶——云龙绿茶优良品质形成的影响。     

不同加工工艺对针形绿茶品质的影响

用相同原料、经过相同杀青与揉捻后，采用不同做形工艺制作针形绿茶。结果表明，其成茶品质有一定的差异：以手工做形和以理条机做形辅以手工做形的加工工艺，其成茶品质较好。     

海水贝类风味品质研究进展

贝类作为海水养殖的重要经济品种,因其鲜美的风味感官和独特的营养价值而深受人们喜爱。风味是贝类品质评价的一项重要指标,风味物质分为气味物质和呈味物质两大类。本文对国内外经济海水贝类风味物质的形成、作用及其在加工贮藏中的变化情况进行综述;其次,以生化代谢水平以及生命活力状态为指标,对活品贝类的品质研究进行总结;最后,介绍了感官评价、色谱-质谱联用、代谢组学、风味指纹图谱等风味品质评价技术。本篇综述以期为海水贝类的风味品质研究提供参考。     

基于气味在线检测的绿茶锅式杀青系统研究

在传统的锅式杀青装置基础上,植入PEN3电子鼻进行气味在线检测,通过研究不同锅温下PEN3电子鼻代表性传感器响应值与杀青品质的关系,提出基于气味在线检测的绿茶锅式杀青系统,根据酶促氧化物以及绿茶香气的测量值来反馈控制杀青锅温.结果表明:杀青锅温过低会导致前期酶促氧化严重,过高会导致香气散失过多,因此在前期灭酶完成后立刻...     

夏季茶鲜叶加工花香型绿茶工艺技术研究

以茶树品种碧香早的夏季一芽一叶茶鲜叶为原料,在传统绿茶加工工艺基础上,将"做青(晒青、晾青、摇青、静置)"工艺技术融入其摊放工序中,通过感官审评及滋味、香气品质成分分析,优化夏季茶鲜叶加工花香型绿茶的"做青"工艺技术。结果表明,采用晒青5 min、晾青0.5h、晒青5min,晾青0.5h,10r/min摇青10转,静置1h,15r/min摇青60转为最佳"做青"工艺,加工出的夏季绿茶花香显露,滋味醇正,苦涩味降低,水浸出物、氨基酸、可溶性糖含量分别比传统工艺绿茶增加了1.29%,11.08%,10.50%,而茶多酚、儿茶素含量、酚氨比、酯型儿茶素/简单儿茶素则分别降低了6.05%,2.35%,15.38%,19.15%;同时新增了苯甲醇、柏木醇、α-合欢烯、柠檬醛等花香成分,且香草醇、橙花醇的相对含量高于传统工艺绿茶;说明在传统绿茶加工的摊放工序中融入"做青"工艺技术,可加工出具有花香品质的夏季绿茶。     

聚乙烯聚吡咯烷酮(PVPP)吸附对茶饮料风味 品质的影响

目的 通过聚乙烯聚吡咯烷酮(PVPP)过滤吸附除去茶饮料中非生物稳定性物质来研究其对饮料风味品质的影响。方法 茶汤样品经PVPP过滤处理后, 对理化指标、感官品质及特征成分进行分析与全面评价。结果 分析表明PVPP对一般性指标和基本风味物质的影响很小, 说明PVPP处理不会对饮料造成显著影响, 但对特征性指标苦味值表没食子儿茶素没食子酸酯(EGCG)、表儿茶素没食子酸酯(ECG)和香味物质顺-3-己烯醇、苯乙醇有一定的影响。结论 研究表明PVPP能有效地除去茶饮料中的敏感多酚与蛋白, 可明显提高非生物稳定性, 合理利用PVPP调控饮料中多酚含量及构成, 有利于茶饮料风味的改善与保持。     

茶香风味鸡肉火腿肠的研制

介绍一种新香型鸡肉火腿肠的研发思路和相关技术;通过对市场现有鸡肉类产品的分析,搭配绿茶的特征香气及茶多酚的养生概念,研制成功茶香风味鸡肉火腿肠;并介绍其生产需要的配方、工艺和过程参数,以及相关的市场分析;该产品旨在丰富国内鸡肉类产品系列,提供新的香气享受给消费者,同时也可扩大清真类产品。     

铜仁绿茶品质的研究

对铜仁市辖区内随机抽取的33个茶园及其深加工产品进行调研,按照相关国家标准实施检验建立数据库,将检验结果与绿茶的国家标准和贵州地方标准进行比较和分析,得出铜仁绿茶的水分3.65%、粉末0.078%、总灰分5.19%、水浸出物42.59%、粗纤维8.57%、铅0.58g/kg各项指标都远远优于国家标准和贵州地方标准的结论,进而对铜仁绿茶品质进行定位,为制定铜仁绿茶标准提供数据资料。      

Effect of nanocomposite‐based packaging on preservation quality of green tea

An improved nanocomposite‐based packaging material (NCP) was prepared by blending polyethylene with nano‐Ag, nano‐TiO₂ and attapulgite. And its effect on preservation quality of green tea (Biluochun and Qingfeng) during one‐year ambient storage was investigated. The results showed that adding nanoparticles to the polyethylene could significantly improve the barrier property. After one‐year ambient storage, the moisture of Biluochun and Qingfeng with NCP was decreased by 10.3% and 6.1% compared with the normal packaging material. Meanwhile, the contents of amino acid, tea polyphenols, chlorophyll and ascorbic acid were increased by 22.8%, 9.4%, 30.4% and 9.5% for Biluochun and 19.2%, 9.3%, 27.3% and 21.6% for Qingfeng, respectively, compared with the normal packaging material. Moreover, the sensory quality of NCP was also superior to that with the control. Therefore, the improved NCP material probably provides an attractive alternative to maintain the preservation quality of green tea at a high level during storage.     

浮梁槠叶种夏茶加工成红茶和绿茶的品质化学成分变化

目的 比较浮梁槠叶种(Castanopsis sinensis)夏茶加工成红茶和绿茶的品质化学成分变化,研究其适制性。方法 将浮梁产槠叶种夏茶分别加工成红茶和绿茶,采用国家标准方法等测定其滋味成分,采用顶空固相微萃取-气相色谱-质谱法(headspace solid-phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)分析其挥发性物质相对含量,比较两者的品质化学成分差异。结果 茶青中游离氨基酸含量为3.86%,低于红茶中的4.43%(P<0.05),高于绿茶中的3.68%(P<0.05);而酚氨比为3.22,高于红茶中的1.45,低于绿茶中的3.79;多糖含量为6.77%,高于红茶中的6.14%(P<0.05),略高于绿茶中的6.70%(P>0.05);咖啡碱含量为2.83%,略低于红茶中的2.96%(P>0.05),高于绿茶中的1.81%(P<0.05)。挥发性物质分析结果表明,红茶中以花果香、柠檬香、薄荷香等为主的β-紫罗兰酮、水杨酸甲酯、D-柠檬烯、(...     

Effect of selenium spraying on green tea quality

This research was conducted to determine the effects of different selenium treatments on the sensory and chemical qualities of green tea harvested in the summer tea‐producing season. Green tea was produced from fresh tea leaves sprayed with sodium selenite or organically bound selenium solution. The results showed that the sweetness and aroma of green tea extracts were significantly increased and the astringent taste and bitterness were significantly reduced by selenium spraying during the summer tea‐producing season. Significant differences in astringent taste, bitterness and sweetness of green tea extracts were found between sodium selenite and organically bound selenium treatments. The total amino acid and vitamin C contents of green tea were significantly increased and the ratio of polyphenols and amino acids was significantly decreased by selenium spraying. The vitamin C content of green tea during storage was more stable as a result of selenium treatment. No significant difference was found between sodium selenite and organically bound selenium treatments. These results demonstrate that the sensory and chemical qualities of green tea were significantly improved by selenium spraying. © 2001 Society of Chemical Industry     

Effect of water quality on the nutritional components and antioxidant activity of green tea extracts

Green tea extracts (GTEs) were prepared with tap water (TW), activated carbon adsorbed water (AC), deionized water (DI), distilled water (DW), reverse osmosis water (RO) and ultra-pure water (UP). Their nutritional components were determined by chemical methods. Deoxyribose assay and the xanthine oxidase method were applied to test the antioxidant activities of GTE in vitro. The results indicated that there were statistically significant differences (P < 0.05) in the yield rate, the contents of polyphenols, catechins, caffeine, copper, lead and fluorine. Among them, DI gave the greatest yield rate and polyphenols, with low caffeine, DW increased the contents of non-ester catechins and AC enhanced the concentrations of ester catechins. The contents of copper and lead in GTEs were highly correlated with those of the tested water (r = 0.767 and 0.871, respectively). Fluorine contents in all GTEs were above 6.0 g kg⁻¹. GTEs prepared with RO displayed the highest antioxidant activities among the six GTEs.