福鼎大白茶树鲜叶不同茶制品活性成分比较

目的 分析比较福鼎大白茶树鲜叶加工制成的3种茶类中活性成分的含量差异。方法 以福鼎大白茶树鲜叶为原料, 按不同工艺制成绿茶、白茶、红茶, 测定其活性成分(茶多酚、咖啡碱、氨基酸、儿茶素)含量。结果 绿茶中茶多酚及儿茶素总量最高, 红茶较低。绿茶中儿茶素总量约为红茶的10倍, 白茶中儿茶素总量约为红茶的8倍; 氨基酸含量: 白茶高于绿茶及红茶, 红茶中氨基酸最低; 咖啡碱在白茶和绿茶中的含量差别不大, 显著性高于红茶, 但不存在极显著性差异。结论 加工工艺对不同茶类茶多酚及儿茶素类物质含量影响较大, 而对咖啡碱含量的影响不大。     

The effects of altitude on the chemical composition of black tea

Changes in quality parameters of crush, tear and curl (CTC) black clonal teas due to variations in altitude within a radius of 10 km were determined. There were significant (P = 0.05) changes in all the quality parameters due to areas of production despite the short sampling radius. The Group I volatile flavour compounds (VFC) increased with decrease in altitude whereas Group II VFC and flavour index (FI), theaflavins (TF), thearubigins (TR) (except in clone TN 14-3) and caffeine increased with increase in altitude. The tasters' evaluation also increased with increase in altitude.     

Analysis of the theaflavin composition in black tea (Camellia sinensis) for predicting the quality of tea produced in Central and Southern Africa

A parameter of black tea that correlates with quality is highly desired. Twenty good and 20 poor quality tea clones were selected from the breeding programme at the Tea Research Foundation (Central Africa) (TRF(CA)). The theaflavin (TF) composition of the black tea manufactured from each clone was analysed by capillary electrophoresis and correlated with total scores and valuation from two tea tasters with regression analysis. The significance of the differences between the 20 good and 20 poor quality tea clones was determined with the Student t‐test and the distribution‐free Kruskal–Wallis test. The sum of the TFs of the black tea correlated well (r = 0.785, P = 0.0002) with the value of the tea. Of the individual TFs determined in the black tea, the highest correlation was obtained with TF‐3′‐monogallate (TF‐B) (r = 0.788, P = 0.0016), TF‐3‐monogallate (TF‐A) (r = 0.741, P = 0.0004) and free TF (TF‐f) (r = 0.705, P = 0.0002). TF‐B (m = 24.90) followed by TF‐A (m = 12.48) showed the steepest slopes against value, making them good indicators for value. The TF‐digallate (TF‐dg) content did not show significant correlation with value (r = 0.316, P = 0.358). The individual TF content thus can be used for optimising the black tea manufacturing process in Central and Southern Africa. © 2002 Society of Chemical Industry     

Hastening of leaf senescence in the processing of green tea leaf to black tea

The current system of processing green tea leaf (Camellia sinensis) to produce black tea involves a long period, especially because of the withering process practised in acquiring leaf senescence which is essential to impart fullness to the resulting tea liquors. Hastening leaf senescence by artificial withering at temperatures favourable to enzymic transformations accelerated the process and considerably shortened the manufacture of black teas.     

单核苷酸多态性在茶树中应用的研究进展

茶树原产于中国西南地区,是一种重要的经济作物。茶叶作为中国的传统饮品,是世界上三大无酒精饮料之一。长期的自然演化及自交不亲和使得茶树的种质资源极其丰富。单核苷酸多态性(single nucleotide polymorphism,SNP)是基因组水平上单核苷酸突变引起的基因序列多样性,是继限制性酶切片段多态性(restriction fragment length polymorphism,RFLP)和简单序列重复(simple sequence repeat,SSR)的第3代分子标记,广泛存在于生物基因组中。SNP分子标记作为最重要的分子标记技术对遗传学研究有极其重要的作用。本文介绍了SNP分子标记的特征,综述了SNP在茶树中的开发检测方法,研究应用于分子标记、基因定位、关联分析等,旨在为理解和研究SNP分子标记在茶树中的研究应用提供参考。     

Riboflavin and health: A review of recent human research

There has lately been a renewed interest in Riboflavin owing to insight into its recognition as an essential component of cellular biochemistry. The knowledge of the mechanisms and regulation of intestinal absorption of riboflavin and its health implications has significantly been expanded in recent years. The purpose of this review is to provide an overview of the importance of riboflavin, its absorption and metabolism in health and diseased conditions, its deficiency and its association with various health diseases, and metabolic disorders. Efforts have been made to review the available information in literature on the relationship between riboflavin and various clinical abnormalities. The role of riboflavin has also been dealt in the prevention of a wide array of health diseases like migraine, anemia, cancer, hyperglycemia, hypertension, diabetes mellitus, and oxidative stress directly or indirectly. The riboflavin deficiency has profound effect on iron absorption, metabolism of tryptophan, mitochondrial dysfunction, gastrointestinal tract, brain dysfunction, and metabolism of other vitamins as well as is associated with skin disorders. Toxicological and photosensitizing properties of riboflavin make it suitable for biological use, such as virus inactivation, excellent photosensitizer, and promising adjuvant in chemo radiotherapy in cancer treatment. A number of recent studies have indicated and highlighted the cellular processes and biological effects associated with riboflavin supplementation in metabolic diseases. Overall, a deeper understanding of these emerging roles of riboflavin intake is essential to design better therapies for future.     

Uptake of fluoride by tea plant (Camellia sinensis L) and the impact of aluminium

Tea plant (Camellia sinensis L) accumulates large amounts of fluoride in mature leaves from soils of normal fluoride availabilities, but the properties of fluoride absorption by this plant species are not well understood. The present study examined the characteristic of fluoride uptake by tea plants and the impact of Al with solution and soil experiments. The results showed that the fluoride taken up by tea plants was largely and readily transported, in particular to the leaves. The fluoride in leaves increased linearly with fluoride concentrations in the uptake solution (R² = 0.75, P < 0.001) or in the soil (R² = 0.88, P < 0.001), whereas those in root and stem were only marginally influenced. Including Al in solution or adding Al to the soil apparently increased the uptake and translocation of fluoride to the leaves. The concentrations of fluoride in the leaves were significantly (P < 0.05) increased by 19.1% or 37.7% when 18.5 µmol l^?1 Al or 74.1 µmol l^?1 Al respectively was included in the uptake solution, compared with the control without Al during an uptake period of 22 h. Similarly, Al application (100 mg kg^?1) to soil led to significantly higher fluoride concentrations in mature leaves and new shoots (one bud with three leaves). By contrast, the concentrations of Al in leaves in solution and soil experiments were not affected by fluoride and Al treatments. Nevertheless, higher Al concentrations after Al and fluoride additions were observed in the new shoots in soil experiments. Copyright © 2003 Society of Chemical Industry     

我国预防控制肥胖策略的探讨

肥胖不仅是一种疾病,而且是其它慢性病的危险因素。肥胖已经成为我国一个严重的公共卫生问题和主要的疾病负担。防控肥胖可以减少相关慢性病的发病和死亡。我国控制和预防肥胖刻不容缓,预防是解决问题的关键,预防肥胖要从儿童少年时期开始,采取政府主导、多部门合作和社会积极参与是最有效的防控策略。     

The effects of food essential oils on cardiovascular diseases: A review

Essential oils (EO) are complex secondary metabolites, which are produced by aromatic plants and identified by their powerful odors. Present studies on EO and their isolated ingredients have drawn the attention of researchers to screen these natural products and evaluate their effect on the cardiovascular system. Some EO, and their active ingredients, have been reported to improve the cardiovascular system significantly by affecting vaso-relaxation, and decreasing the heart rate and exert a hypotension activity. Several mechanisms have been proposed for the role of EO and their main active components in promoting the health of the cardiovascular system. The objective of this review is to highlight the current state of knowledge on the functional role of EO extracted from plants for reducing the risk of cardiovascular diseases and their mechanisms of action. Research on EO has the potential to identify new bioactive compounds and formulate new functional products for the treatment of cardiovascular diseases such as arterial hypertension, angina pectoris, heart failure, and myocardial infarction.     

Understanding the biosyntheses and stress response mechanisms of aroma compounds in tea (Camellia sinensis) to safely and effectively improve tea aroma

Abstract

Metabolite formation is a biochemical and physiological feature of plants developed as an environmental response during the evolutionary process. These metabolites help defend plants against environmental stresses, but are also important quality components in crops. Utilizing the stress response to improve natural quality components in plants has attracted increasing research interest. Tea, which is processed by the tender shoots or leaves of tea plant (Camellia sinensis (L.) O. Kuntze), is the second most popular beverage worldwide after water. Aroma is an important factor affecting tea character and quality. The defense responses of tea leaves against various stresses during preharvest (tea growth process) and postharvest (tea manufacturing) processing can result in aroma formation. Herein, we summarize recent investigations into the biosyntheses of several characteristic aroma compounds prevalent in teas and derived from volatile fatty acid derivatives, terpenes, and phenylpropanoids/benzenoids. Several key aroma synthetic genes from tea leaves have been isolated, cloned, sequenced, and functionally characterized. Biotic stress (such as tea green leafhopper attack) and abiotic stress (such as light, temperature, and wounding) could enhance the expression of aroma synthetic genes, resulting in the abundant accumulation of characteristic aroma compounds in tea leaves. Understanding the specific relationships between characteristic aroma compounds and stresses is key to improving tea quality safely and effectively.

     

Studies on fatty acid composition in tea Camellia sinensis

The proportions of fatty acids, viz lauric, myristic, palmitic, oleic, linoleic, and linolenic, in tea leaf, Camellia sinensis (L) O Kuntze, were determined at different stages of manufacture as well as in Mack tea. No significant variations were observed in the fatty acid contents of three major cultivars, Assam, China and Cambod. However, some variations were noticeable in leaf cropped in different months. Manufacturing stages have a pronounced effect on the relative proportions of the various fatty acids. Monthly distribution of total lipid was also followed in tea leaf, and the pattern of variation observed was identical for all the three cultivars.     

Differentiation of eight tea (Camellia sinensis) cultivars in China by elemental fingerprint of their leaves

BACKGROUND: Tea is an infusion made from dried leaves of tea (Camellia sinensis) and can be a good dietary source of essential trace metals for humans. Therefore, it is necessary to consider variations in element content of tea leaves among tea cultivars. Thus, elemental fingerprint techniques, based on elemental contents (Al, B, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, and Zn) determined by inductively coupled plasma atomic emission spectrometry (ICP‐AES) and multivariate statistical analysis, have been used to differentiate eight tea cultivars. RESULTS: The ranges of element concentrations in leaves of the eight cultivars were in good agreement with those obtained in previous studies and the level of most elements in tea leaves was significantly different among cultivars. The classifications of eight tea cultivars were 100% accurate in total by principal component analysis (PCA), hierarchical cluster analysis (HCA), linear discriminant analysis (LDA), and back‐propagation neural network (BPNN) analysis. CONCLUSION: Each cultivar presented a distinctive element fingerprint and the elements in tea leaves can be significant predictors in differentiating tea cultivars. Copyright © 2009 Society of Chemical Industry     

体外模拟消化体系中油茶多酚以及抗氧化活性的变化

为了研究油茶蒲提取物在消化过程中成分和抗氧化活性的变化,本研究以油茶蒲为原料,研究模拟人体体外消化过程中成分及其抗氧化活性的变化。结果表明,在模拟体外消化的前后油茶蒲提取物总酚含量稍有下降,而HPLC分析中多数酚类物质出现增长,其中鞣花酸增长了4.56倍。体外抗氧化体系中,DPPH?和ABTS?与总酚含量变化一致,呈下降趋势,而?OH的清除能力出现明显增长。综上,研究发现经体外消化油茶蒲提取物总酚含量会降低,而小分子酚酸增长,有利于后续的吸收,同时也,使其对?OH的清除能力增加。     

茶多酚对心血管保护作用的研究进展

2015年世界卫生组织报道,心血管疾病已成为全球的主要死因之一,死于心血管疾病的人数逐年上升。大量实验证明茶多酚在抗动脉粥样硬化、降血压、降血脂、心肌保护、血管保护、抗心律失常和心肌缺血再灌注损伤等心血管保护作用方面均有较好的效果。本文对近年来茶多酚在防治心血管疾病方面的研究进展进行综述,概述了其心血管防护作用及机理,分析了我国茶多酚的研究现状,并对茶多酚的应用前景进行了展望,旨在为茶多酚在心血管疾病防治方面的应用提供参考。     

茶多酚对肥胖大学生体质的改善作用

对茶多酚改善在校肥胖大学生体质的作用进行了研究.结果表明,茶多酚可降低肥胖学生体脂含量、维持正常血压、提高肺活量,但对台阶指数的提高不甚明显.