乳酸菌发酵茶花粉对α-葡萄糖苷酶抑制率的影响

目的：提高茶花粉α-葡萄糖苷酶抑制率。方法：以α-葡萄糖苷酶抑制率为指标,采用响应面试验优化乳酸菌接种量、发酵温度及发酵时间对茶花粉发酵效果的影响。结果：复合乳酸菌菌粉接种量对α-葡萄糖苷酶抑制率影响最大,其次是发酵温度。发酵茶花粉的最优工艺条件为乳酸菌接种量0.9%、发酵温度37℃,发酵时间3d,该条件下茶花粉发酵液对α-葡萄糖苷酶的抑制率为38.97%,是未发酵的3.11倍。结论：试验优化的乳酸菌发酵茶花粉工艺操作简单,能显著提高α-葡萄糖苷酶抑制率。     

酶解发酵对玉米面粉黏度研究

研究酶解发酵法处理玉米。通过酶解发酵法制得的玉米粉的性质测定,结果表明：经酶解发酵的玉米面粉黏度降低,不符合面团的质量要求。     

加工工艺对桑寄生茶品质及功能活性的影响

目的:探讨不同加工工艺对桑寄生茶品质及功能活性的影响。方法:采用自然发酵、杀青、冠突曲霉发酵等3种加工技术进行工序组合,制备8种不同的桑寄生茶样品,进而测定8种桑寄生茶的主要化学成分、抗氧化活性及对α-淀粉酶的影响,并对8种桑寄生茶进行感官审评。结果:经杀青处理的桑寄生茶能提升水浸出物、游离氨基酸、茶多酚、总黄酮、可溶性糖等5种化学成分的含量（P<0.05）及抗氧化活性;经自然发酵处理的桑寄生茶清香气加强;冠突曲霉发酵处理桑寄生茶能显著提升α-淀粉酶的酶活力（P<0.05）。其中,杀青处理能最大程度提升桑寄生茶的主要化学成分含量、抗氧活活性;杀青结合冠突曲霉发酵处理桑寄生茶具有一定的抗氧化活性及风味特点,且能双向调节α-淀粉酶的活性。结论:杀青、杀青结合冠突曲霉发酵等加工技术在品质、功能活性上各有明显优势,可作为关键加工技术用于制作品质优异的桑寄生茶。     

粗壮脉纹胞菌复合多菌种发酵茶粕产纤维素酶的研究

用粗壮脉纹胞菌分别复合东方伊莎酵母、里氏木霉、绿色木霉、乳酸杆菌固态发酵已去除茶皂素的茶粕,通过测定发酵产物中3种纤维素酶：外切葡聚糖酶（C1）、内切葡聚糖酶（Cx）、β-葡萄糖苷酶（β-G）及总酶滤纸酶（filter paper activity,FPA）的酶活力来探讨其分解粗纤维素的协同作用。粗壮脉纹胞菌和绿色木霉混合发酵产生的C1酶酶活力较粗壮脉纹胞菌单菌发酵提高了51.09%,粗壮脉纹胞菌和绿色木霉复合发酵较单菌发酵延长了其纤维素酶分泌的周期,96 h时FPA酶活力达到2.782 U/g;粗壮脉纹胞菌复合里氏木霉、绿色木霉混合发酵组在发酵10 d后对茶粕粗纤维的最终降解率分别达到了64.19%和61.59%;接种量对单菌和混合菌发酵产纤维素酶影响总体趋势是随着接种量增加酶活力提高,但粗壮脉纹胞菌单菌发酵纤维素酶酶活力在接种量超过9 mL/100 g后开始下降。表明粗壮脉纹胞菌复合里氏木霉、绿色木霉混合发酵降解纤维素具有协同作用。     

非酿酒酵母产生的β-葡萄糖苷酶在发酵酒中的应用研究进展

β-葡萄糖苷酶对糖苷键的水解作用已被广泛应用于酿酒、茶增香、保健品开发等领域.发酵环境中非酿酒酵母产生的β-葡萄糖苷酶活力高于酿酒酵母,可在酿酒酵母酶活力不足时进行补充.本文对发酵过程中不同的影响因素如酵母合成和释放β-葡萄糖苷酶的能力、发酵环境中的温度、酸碱度和可发酵糖浓度等对β-葡萄糖苷酶活力的影响进行了综述,并对...     

人工智能酶促发酵与红茶天然产物品质形成

为了解决目前红茶加工过程,发酵工序大都是依靠制茶人员凭经验掌握,产品质量难以控制的问题,特开展了人工智能酶促发酵工艺及对红茶天然产物品质形成研究。人工智能系统由智能程控无菌发酵室、远红外碳纤维加热器、超声波雾化加湿器、智能供氧装置、臭氧发生器和紫外线灯等组成,并且采用茶叶内含多酚氧化酶和外源糖化酶双重酶促发酵方法。结果表明,该工艺不但使红茶中茶多酚、茶多糖、氨基酸、芳香物质等天然产物转化形成多,色香味形品质优佳,而且可提高工效25%~30%,节约生产成本15%~20%,为我国红茶加工开创了高新工艺技术。     

移动式填充床固态发酵反应器的设计及单宁酶中试发酵

通过对单宁酶固态发酵工艺分析,结合传统厚层通风制曲的结构,设计了移动式填充床固态发酵反应器。利用设计的固态发酵反应器以发酵茶梗为基质中试化生产单宁酶,探究10、15、20 m3/h通风量对单宁酶中试化发酵效果。结果表明:在通风量为10、15、20 m3/h的条件下,发酵达到的最大酶活分别为8.21、8.08、8.41 U·gds-1,达到最大酶活的时间分别96、120、144 h。利用设计的填充床固态发酵反应器以茶梗为基质发酵生产单宁酶,不仅原料来源广泛、价格低廉,还能有效提高单宁酶酶活。     

不同加工工艺对蒲公英叶茶品质及抗氧化活性的影响

以蒲公英叶为研究对象,分别利用传统工艺、渥堆发酵以及添加β-葡萄糖苷酶发酵工艺加工成蒲公英绿茶和红茶,并通过汤色色差评价、功能性成分定量分析、香气组分分析、抗氧化能力分析以及感官评价,以期确定蒲公英叶茶加工的最佳工艺。经过β-葡萄糖苷酶发酵的蒲公英叶茶能获得较佳的汤色品质,未经过发酵工艺的蒲公英绿茶能保留较高的黄酮、多糖以及蛋白质成分,分别为1.42%、7.23%以及1.81%。未添加β-葡萄糖苷酶渥堆发酵的蒲公英红茶含有最多嗅感化合物,包括糠醇、5-甲基呋喃醛、大茴香醛、乙酸甲酯、苯乙酸甲酯、2-乙基丁酸、2-甲基四氢呋喃-3-酮、2,3-辛二酮等18种特有香气物质,主要表现为甜香、山楂、可可、肉类、爆米花等令人愉快的香气,为其获得较高感官评价香气评分奠定了物质基础,且其总抗氧化能力、DPPH清除率以及羟基自由基清除率分别为3.87 mmol/L FeSO₄·7H₂O、73.99%和34.21%,具有显著性的抗氧化能力。不同加工工艺制作的蒲公英叶茶品质及抗氧化活性存在差异性,其中渥堆发酵工艺较为适合蒲公英叶茶的制作。     

黑曲霉与普洱茶品质形成关系的探讨

普洱茶品质的形成是微生物(优势菌种黑曲霉)和酶系综合协调作用的结果,从普洱茶的化学成分、品质特征、渥堆发酵、功效、食品安全等方面作了分析,探明黑曲霉在普洱茶品质形成中具有重要作用.     

发酵牛蒡茶的风味物质与营养成分研究

将牛蒡进行人工接种发酵制备牛蒡茶,分析测定牛蒡茶的主要营养成分、抗氧化能力及风味物质组成,并与烘烤牛蒡茶和自然渥堆发酵牛蒡茶比较,以此评价人工发酵牛蒡茶的功能性品质。结果表明:人工接种发酵牛蒡茶中可溶性糖和总黄酮含量较自然渥堆发酵的含量分别提高10.41%和13.17%,并且游离氨基酸含量为1279.70mg/100g DW,呈味氨基酸含量高,人工接种发酵牛蒡茶中共检出了97种风味物质,其中醇类、酸类和醛类等物质的种类比烘烤牛蒡茶均有所增加,结合感官评定发酵牛蒡茶口味醇甜回甘,风味醇香。     

Study of aroma compound formations and transformations during Jinxuan and Qingxin oolong tea processing

We characterised the formation and dynamic changes in the main aroma compounds produced during the manufacturing process of Jinxuan and Qingxin oolong tea. Thirty-five aroma compounds were investigated. Subsequent principal component and cluster analyses showed that the fresh leaves, spread leaves and rocked leaves of the two varieties of tea were distinguished from each other. Particularly, the aldehyde and ‘other’ compounds showed the highest correlation coefficients (0.71 and −0.70) among the principal. The heat map showed that the proportions of acetic acid, 3-methylbutanal and 2-methylbutanal significantly changed during the manufacturing process of the two tea varieties. The key amino acids (isoleucine, leucine, valine and aspartic acid) and enzymes (branched-chain amino acid aminotransferase, aspartate aminotransferase and acetaldehyde dehydrogenase) involved in the synthesis of 3-methylbutanal and 2-methylbutanal differed between the two varieties during manufacture. Our study reveals the characteristics of different varieties of oolong tea and their aroma formation after manufacture using the same process.     

Changes in enzyme activities (polyphenol oxidase and phenylalanine ammonia lyase) with type of tea leaf and during black tea manufacture and the effect of enzyme supplementation of dhool on black tea quality

Variation in polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) activities with respect to different cultural and manufacturing processes and their effects on black tea quality were studied. There was a wide variation between enzyme activities of different clones, as well as variation due to seasonal changes and shoot maturity. Field practices such as plucking rounds and pruning had a great impact on enzyme activities. The enzyme activities positively correlated with tasters' scores. The extent of change in enzyme activities at different stages of manufacture differed widely. The loss of activity during withering could be restored by rehydration. Residual activity was observed in made tea. Supplementation of enzymes enhanced the black tea quality markedly in terms of cuppage and creaming properties.     

日本制茶新技术及新产品

日本制茶新技术主要是:(1)利用冷冻→减压→高频干燥新工艺制作速溶茶。(2)利用远红外加温萎凋及调整pH值和充氮技术提高乌龙茶与乌龙茶罐装茶水质量。(3)添加天然植物芳香物质提高茶叶香气。(4)应用“半透膜”浸透技术加工冰茶以及冷冻真空干燥新工艺制作绿茶。目前开发的茶叶新产品有:(1)茶藻保健茶及其液态饮料。(2)粉末红茶与速溶红茶。(3)富钙高维茶等。     

Characterisation of white tea – Comparison to green and black tea

An overview is given on the manufacture of the different types of tea along with the most important phenolics present in tea and methods of analysis. Compositional data are presented for green, white and black teas. A differentiation of green and black tea by using the ratio between total phenolics and sum of the major catechins seems to be feasible. For white tea there is no general accepted definition. Possible approaches are geographic origin, the botanical variety and the manufacture or the appearance. The differentiation between green and white teas by the ratio mentioned above is not possible.     

Characterisation of white tea – Comparison to green and black tea

An overview is given on the manufacture of the different types of tea along with the most important phenolics present in tea and methods of analysis. Compositional data are presented for green, white and black teas. A differentiation of green and black tea by using the ratio between total phenolics and sum of the major catechins seems to be feasible. For white tea there is no general accepted definition. Possible approaches are geographic origin, the botanical variety and the manufacture or the appearance. The differentiation between green and white teas by the ratio mentioned above is not possible. An erratum to this article is available at .     

Changes in content of organic acids and tea polyphenols during kombucha tea fermentation

Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Tea polyphenols which includes (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG) and theaflavin (TF) have been reported to possess various biological activities. The present study focused on changes in content of organic acid and tea polyphenols in kombucha tea prepared from green tea (GTK), black tea (BTK) and tea manufacture waste (TWK) during fermentation. Concentration of acetic acid has reached maximum up to 9.5 g/l in GTK on 15th day and glucuronic acid concentration was reached maximum upto 2.3 g/l in BTK on 12th day of fermentation. Very less concentration of lactic acid was observed during the fermentation period and citric acid was detected only on 3rd day of fermentation in GTK and BTK but not in TWK. When compared to BTK and TWK very less degradation of EGCG (18%) and ECG (23%) was observed in GTK. TF and thearubigen (TR) were relatively stable when compared to epicatechin isomers. The biodegradation of tea catechins, TF and TR during kombucha fermentation might be due to some unknown enzymes excreted by yeasts and bacteria in kombucha culture.     

微波加热在茶叶加工中的应用

微波加热适用于绿茶加工，研究出一台可用于名优绿茶加工的茶叶微波加工设备，设备的微波输出功率为6kW(2450MHz)，输送带宽度为42cm，速度无级变速。绿茶加工中，微波杀青时间需2min左右（6kW），微波分段干燥的时间约5min(6kW)，微波杀青和微波干燥的茶叶感官品质优于常规方法，氨基酸、咖啡碱和水浸出物的含量也高于常规茶。     

共固定化单宁酶和β-葡萄糖苷酶对茶饮料增香和除混效果的研究

以海藻酸钠为载体,采用交联-包埋-交联的方法共固定化了单宁酶和β-葡萄糖苷酶,2种酶的活力回收率分别为67·3%和46·0%。将共固定化酶应用于茶饮料的除混和增香,结果表明,经共固定化酶处理后,绿茶、红茶、乌龙茶3类茶的香精油总量均有所增加,其中以绿茶的香精油总量增加最多,增长率达20·69%,乌龙茶和红茶分别为10·30%,6·79%;3类茶的非酯型儿茶素含量增加,增幅依次为绿茶(52·17%)>红茶(12·94%)>乌龙茶(8·83%),而酯型儿茶素的含量下降,降幅依次为绿茶(20·0%)>乌龙茶(16·68%)>红茶(5·04%);实验中还研究了用共固定化酶处理绿茶饮料的抗沉淀效果,未经共固定化酶处理的绿茶饮料低温时的浊度比经共固定化酶处理的要高,贮藏3个月,经共固定化酶处理的绿茶的澄清度一直很高,而未经共固定化酶处理的绿茶在60d后有少许沉淀产生。     

绿茶面条加工工艺优化及护色技术研究

以超微绿茶粉、特一粉为主要原料,以葡萄糖酸锌和叶绿素铜钠为主要护色剂,对绿茶面条的加工工艺及护色方法进行了研究。在单因素实验基础上,进行正交实验,利用方差分析及多重比较,对绿茶面条加工工艺进行了优化。绿茶面条的优化加工工艺为海藻酸钠添加量0.20%,超微绿茶粉添加量1.5%,葡萄糖酸锌添加量0.018%,叶绿素铜钠添加量0.010%,水添加量26%。以上5个因素在影响绿茶面条品质上的优先次序为超微绿茶粉添加量>叶绿素铜钠添加量>水添加量>葡萄糖酸锌添加量>海藻酸钠添加量。所制得的绿茶面条色泽翠绿、均匀,外形整齐,表面细密光滑,咬劲、软硬、弹性均适口,具有绿茶特有的香味。     

Effects of enzymatic action on the formation of theabrownin during solid state fermentation of Pu-erh tea

BACKGROUND: Theabrownin (TB) is a main bioactive component in Pu‐erh tea, and the total amount is between 100 and 140 g kg^?1. However, reports on the mechanism of formation of TB are sparse because it has a high molecular weight and complex composition. Hence, the mechanism of formation of TB in Pu‐erh tea during solid state fermentation was investigated using an exogenous enzyme method. RESULTS: It was found that, in the presence of exogenous enzymes, the tea liquor prepared from the resulting leaves changed considerably in colour. In addition, the TB, total carbohydrate, polysaccharide, amino acid and protein contents were all increased, while the tea polyphenol content decreased sharply; the surfaces of leaves before fermentation appeared to be smooth and intact, and the structures of the cell, cellulose and lignin were complete, while after fermentation their surfaces were covered by microorganisms and the structures of the cells were largely disrupted. CONCLUSION: The enzymatic actions are closely related to the compositional changes occurring during Pu‐erh tea manufacture, and its quality. Enzymes produced by microorganisms were found to be the main cause of TB formation during the fermentation of Pu‐erh tea. Copyright © 2011 Society of Chemical Industry