Effect of Ultra-Violet B on Release of Volatiles in Tea Leaf

Many volatiles in fresh tea leaf are in the forms bound with glycosides and they are released by action of ß–primeverosidase and ß-glucosidase during tea processing. Effect of ultra-violet B on release of volatiles in fresh tea leaves of two tea cultivars, “Maoxie” and “Anhui-9,” were investigated. Types of volatile and their concentration increased when ultra-violet B was applied at 3.0 μmol m^?2 s^?1 for 2 h and then decreased as the irradiation was extended to 6 h. The relation of expression of ß–primeverosidase and ß-glucosidase genes to the release of volatiles were also discussed.     

The Awesome and Capricious Language of Past,Present and Future Digital Moods

Can cultural progress be held back by linguistic limitations? Architect and educator Marjan Colletti , cofounder of London practice MAM-arch, examines the nouns, adjectives and adjectival compounds used by the architectural profession during the first and second digital turns. He reflects on how restricted vocabularies can cause initially forward-looking concepts to descend into the realm of doctrine and ‘-isms’, and argues that true advancement requires constant evolution of the language employed to describe it.     

茶多酚对大鼠肾缺血再灌注损伤保护作用实验研究

目的探讨茶多酚(Tea polyphenols TP)预处理对大鼠肾缺血再灌注损伤的保护作用及其机制。方法建立大鼠肾缺血再灌注损伤(renal ischemia reperfusion injury RIRI)模型。选用健康SD大鼠42只,随机分为3组:假手术组、单纯肾缺血再灌注损伤组,茶多酚预处理组。于肾缺血再灌注(renal ischemia reperfusion RIR)开始时刻、RIR后2h、RIR后24h分别检测血清肌酐(SCr),血清超氧化物岐化酶(SOD)、血清丙二醛(MDA)、肾组织SOD、肾组织MDA及观察肾组织的病理变化。结果茶多酚预处理组与假手术组相比较,RIRI组SCr水平升高(P<0.05),肾组织及血清中的SOD降低及MDA水平增加(P<0.05)。而茶多酚预处理组SCr、血清MDA和肾组织MDA均比单纯RIRI组低(P<0.05),血清SOD水平及肾组织SOD水平升高(P<0.05)。结论在肾脏缺血再灌注损伤过程中,茶多酚能起到对肾脏的保护作用。     

茶叶组分抗菌、抗病毒和免疫增强作用的研究进展

饮茶对人身体健康有许多益处,如抗氧化、抗衰老、抗肿瘤、降低某些疾病的发病率等。近年来,越来越多的文献报道了茶叶组分具有抗菌、抗病毒和增强人体免疫力的作用。本文对茶叶中的主要组分茶多酚、茶色素、茶多糖和茶氨酸的抗菌、抗病毒和免疫增强作用的研究进展作一综述。     

Application of trace element and stable isotope signatures to determine the provenance of tea (Camelliasinensis) samples

The reputation of particular countries, and plantations within those countries, for the production of high quality tea means that these producers can ask a significantly higher price for their specific product than average. This leads to a temptation for unscrupulous producers to fraudulently label their product as coming from one of these areas to take advantage of this higher price. A simple method for the analysis and verification of the country and plantation of origin of tea would provide security to both tea growers and consumers and would largely stamp out this illegal activity. This paper details the use of complimentary organic and inorganic isotope techniques for the analysis of tea samples from Asia. The application of linear discriminant analysis of the isotope ratios and mineral concentrations permitted 97.6% correct classification of the tea samples using the following variables δD, δ¹³C, ⁴⁹Ti, ⁵³Cr, ⁵⁹Co, ⁶⁰Ni, ⁶⁵Cu, ⁷¹Ga, ⁸⁵Rb, ⁸⁸Sr, ⁸⁹Y, ⁹³Nb, ¹¹¹Cd, ¹³³Cs, ¹³⁸Ba, ¹³⁹La, ¹⁴⁰Ce, ¹⁴¹Pr, ¹⁵³Eu, ²⁰³Tl, ²⁰⁸Pb and ²⁰⁹Bi.     

"湖南毛尖"香味成分的超临界CO2萃取及在烟草中的应用

采用超临界CO2萃取法和四因素四水平的正交试验设计方案考察了"湖南毛尖"茶叶香味成分的最佳萃取条件,并对其萃取物进行了GC/MS分析和卷烟加香试验.结果表明①最佳萃取条件为压力35MPa,温度40℃,时间5h,无水乙醇(夹带剂)用量为茶末质量的3倍.平均萃取率6.15%;②萃取物中含有醇、醛、酮、酯和含氮杂环化合物等24种主要香味成分;③萃取物能明显改善卷烟的吸味,增加香气量,柔和烟气,降低刺激性和杂气.     

Mechanisms of hypolipidemic and anti-obesity effects of tea and tea polyphenols

Among the health-promoting effects of tea and tea polyphenols, the cancer-chemopreventive effects in various animal model systems have been intensively investigated; meanwhile, the hypolipidemic and antiobesity effects in animals and humans have also become a hot issue for molecular nutrition and food research. It has been demonstrated that the body weights of rats and their plasma triglyceride, cholesterol, and LDL-cholesterol have been significantly reduced by feedings of oolong, black, pu-erh, and green tea leaves to the animals. It has been suggested that the inhibition of growth and suppression of lipogenesis in MCF-7 breast cancer cells may be through down-regulation of fatty acid synthase gene expression in the nucleus and stimulation of cell energy expenditure in the mitochondria. The experimental data indicated that the molecular mechanisms of fatty acid synthase gene suppression by tea polyphenols (EGCG, theaflavins) may invite down-regulation of EGFR/PI3K/Akt/Sp-1 signal transduction pathways.     

Structural features,antioxidant and tyrosinase inhibitory activities of proanthocyanidins in leaves of two tea cultivars

In this study the structural features, antioxidant, and tyrosinase inhibitory activities of proanthocyanidins in leaves of two tea cultivars, namely Huangjingui and Qilan, were investigated. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and thiolysis-high performance liquid chromatography-electrospray ionization mass spectrometry analyses confirmed that these proanthocyanidins were built up a mixture of procyanidins, propelargonidins, and prodelphinidins, with the predominance of procyanidins. The proanthocyanidins in leaves of Huangjingui and Qilan cultivars exhibited potent antioxidant activities with IC₅₀ values of 87.36 ± 0.83 and 97.33 ± 0.61 µg/mL in 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, 43.57 ± 0.25 and 55.01 ± 0.22 µg/mL in 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay, and with ferric reducing antioxidant power values of 4.83 ± 0.03 and 3.97 ± 0.02 mmol ascorbic acid equivalent/g in ferric reducing antioxidant power assay. It was also found that these proanthocyanidins had strong inhibition on tyrosinase activity with IC₅₀ values of 54.8 ± 1.27 and 20.0 ± 0.89 µg/mL for Huangjingui and Qilan cultivars, respectively. The results indicated that the proanthocyanidins in leaves of two tea cultivars could be considered as natural antioxidants and tyrosinase inhibitors applied in pharmaceutical and cosmetic industries in the future.     

乌龙茶多糖提取条件的优化

研究了温度、时间、茶水比、pH值对茶多糖（TPS）提取率及活性的影响，结果表明，各因子影响TPS提取率的重要程度依次为pH值、温度、时间、茶水比，影响TPS添生的主要因子是pH值，在酸性或碱性环境下提取的TPS糖含量和蛋白质含量低，活性最低。回归模型的显著性检验达极显著水平（F＞F0.01（14，21）），失拟性检验不显著（F＜F0.05（10，11）），无失拟因素存在，说明模拟较好地拟合TPS提取率与各因子之间的关系。结合TPS提取率及活性测定，利用期望函数途径进行模拟选优，并进行验证，得到TPS提取率的优化条件为温度0.85水平，时间0.60水平，茶／水比0.40水平，pH值－0.95水平。     

茶多酚对鱼糜保藏效果的研究

为解决鱼糜易氧化腐败的难题,将天然抗氧化剂茶多酚、茶多酚＋Vc、茶多酚＋Vc＋柠檬酸添加到鱼糜中,通过对冷藏鱼糜的水分含量、凝胶强度、酸价、过氧化值、挥发性盐基氮等因素变化的研究,探讨茶多酚对鱼糜的保鲜效果。结果表明：茶多酚对冷藏鱼糜具有保鲜效果,Vc有一定增效作用．而柠檬酸增效作用不明显。