茶多糖生物活性及提取纯化的研究进展

茶多糖是一种碳水化合物聚合体,具有降血糖、降血脂、提高机体免疫力、抗凝血、抗血栓、耐缺氧、抗紫外线、杭X射线辐射等一系列特殊保健功能。本文综述了茶多糖的组成、结构、多种特殊功能和茶多糖的提取纯化及其应用。     

茶叶功能成分提取制备专题（五） 茶多糖的提取制备技术

主要介绍了茶多糖的制备技术,包括提取技术和分离纯化方法,并对多种制备技术进行了分析。茶多糖提取与分离纯化方法的搭配组合还需优化,绿色环保与低耗能、低成本是茶多糖制备技术的未来发展趋势。     

茶多糖的化学修饰及体外抗凝血作用研究

采用DEAE-52纤维素柱层析的方法,分离纯化乌龙茶中的多糖成分;选用硫酸化、乙酰化和羧甲基化分别对纯化后的茶多糖进行化学修饰,研究了其修饰前后的体外抗凝血作用。结果表示:茶多糖具有抗凝血作用,能显著延长人体血浆的APTT值,而对TT和PT值无明显影响。茶多糖经柱层析后分离出四个多糖组分,其中组分Ⅱ为茶多糖总量的57.36%,抗凝血活性也相对较强。茶多糖组分Ⅱ经硫酸化、乙酰化和羧甲基化修饰后,抗凝血活性进一步增强,化学修饰试剂与多糖的比例以及修饰反应时间在一定的范围内,影响茶多糖分子结构的变化程度,相应改变抗凝血活性。     

六堡茶多糖理化性质、体外抗氧化及其对人脐静脉血管内皮细胞的保护作用

以六堡茶为原料,利用水提醇沉法制得茶多糖粗品,经脱蛋白纯化后用30%、50%、70%的乙醇溶液进行分段,得到3种六堡茶多糖LTPS-30、LTPS-50和LTPS-70,并分析了其化学组成、分子量分布等理化性质;以自由基清除法(ABTS)和铁离子还原法(FRAP)评价其抗氧化活性;并以Na2S2O3损伤的人脐静脉血管内皮细胞(HUVEC)为模型,探讨了它们对HUVEC氧化损伤的保护作用。结果表明,3种六堡茶多糖样品均为主要含有2个组分的非均一酸性多糖,平均分子量和总糖含量均为LTPS-70LTPS-50LTPS-30;而在蛋白质和总酚含量及两种抗氧化体系下的抗氧化活力均为LTPS-70LTPS-50LTPS-30,且LTPS-70表现出最强的细胞保护作用。说明茶多糖粗品经70%乙醇纯化后具有较强的生物活性,具有良好的应用前景。     

茶多糖的组分及理化性质

粗老茶中含有较高能治疗糖尿病的茶多糖成分。用紫外、红外和气相色谱等方法对茶多糖分析结果表明，它是由糖类、蛋白质、果胶和灰分等物质组成；其多糖部分为阿拉伯糖、木糖、岩藻糖、葡萄糖和半乳糖等，各单糖的组成比例为５．５２：２．２１：６．０８：４４．２０：４１．９９。多糖的分子量约１０７０００。茶多糖的热稳定性较差，高温或过酸和偏碱均会使其中的多糖部分降解。它在沸水中溶解性能较好，但不溶于高浓度的有机溶剂。文中还对粗老茶中的降血糖成分、茶多糖组分和分子量上的差异原因，以及茶多糖中灰分含量高的原因进行了讨论。     

粗茶多糖的膜-纤维素柱色谱分离过程的抗氧化活性研究

以粗茶多糖为原料,经膜分离-纤维素柱色谱法制得分级纯化茶多糖TPs-1、TPs-2和TPs-3,分析比较其清除DPPH、羟基、超氧阴离子等自由基活性变化及其总抗氧化活性表达.结果表明,以10000～20000D的茶多糖为对照,经DEAE-纤维素52吸附分离后分级茶多糖溶液清除自由基活性及总抗氧化能力呈极显著性减弱;纤维素柱色谱分级茶多糖之间来看,DPPH清除率TPs-2>TPs-3>TPs-1,抑制羟基能力TPs-2>TPs-1>TPs-3,抗超氧阴离子活力TPs-1>TPs-2>TPs-3,总抗氧化能力与还原力以TPs-2活性最强.相关性分析表明,茶多糖与总抗氧化能力呈显著正相关,与抑制羟基能力呈显著正相关,纤维素柱色谱分级茶多糖的抗氧化活性表达源于茶多糖的含量变化.     

茶多糖研究的新进展

茶多糖是茶叶中一种重要的功能性大分子。本文从茶多糖的分离纯化工艺的研究、茶多糖结构与结构修饰的研究、茶多糖生物学活性的研究和茶多糖产品的开发利用这四个方面综述了2006年以来茶多糖研究的新成果。分析了茶多糖研究现状与发展新趋势。     

茶多糖化学及生物活性的研究

近年的研究发现茶叶多糖有多种生理作用,非常具有开发前景。它具有降血糖、降血脂、抗血栓、降血压及增强机体免疫力等生理功能,可作为功能保健食品用于糖尿病人、心脑血管病人的辅助治疗。本文就茶多糖的提取纯化方法、纯度测定、分子量测定、化学组成、生理作用等进行综述。     

茶多糖的药理作用研究进展

多糖是由单糖组成的天然高分子化合物,已知的天然多糖约有300多种,广泛存在于植物、动物和微生物组织中,具有多种生理功能,如免疫细胞信息的传递和感受,作为细胞对各种抗原和药物的受体.据大量文献报道,茶多糖具有降低血糖、血脂,增强免疫力,抗动脉粥样硬化,抗凝血,抗血栓的作用,因此,茶多糖可用于对糖尿病、冠心病以及免疫功能低下的治疗.     

茶多糖的分级纯化及组成分析

从粗老绿茶中提取茶叶粗多糖,经DEAE-纤维素DE-52和Sephacryl S-300柱层析纯化,获得三个纯化的茶多糖组分：TPS2-H₂O、TPS2-0.25和TPS2-0.40;此三个组分的中性糖含量分别是：41.23％、29.33％和21.39％,糖醛酸含量分别是：19.5%、22.5%和56.4%,蛋白质含量分别是：未检出、0.8％和未检出;GC-MS分析了三个分级组分均由鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖和半乳糖等六种单糖构成的杂多糖,其摩尔比分别是TPS2-H2O（21.3:13.8:1.8:23.3:6.9:32.9）,TPS2-0.25（60.7:13.4:1.6:2.0:1.2:21.1）,TPS2-0.40（60.2:10.8:4.4:3.2:5.7:15.7）;HPGPC-ELSD法分析了各组分的分布及所占比重。     

稻麦双晚对病虫草发生的影响及解决措施

随着早熟晚粳、中熟晚粳广泛种植,水稻轻型省力栽培方式旱直播的推广,病虫也发生了变化,成熟期显著推迟,下茬无法在适宜播期种植,影响粮食丰产稳产。提出筛选早熟当家品种、大力推广机插秧、加大粮食烘干设备的投入、合理施肥、精准植保等对策。     

Sorghum and millet phenols and antioxidants

Sorghum is a good source of phenolic compounds with a variety of genetically dependent types and levels including phenolic acids, flavonoids, and condensed tannins. Most sorghums do not contain condensed tannins, but all contain phenolic acids. Pigmented sorghums contain unique anthocyanins that could be potential food colorants. Some sorghums have a prominent pigmented testa that contains condensed tannins composed of flavan-3-ols with variable length. Flavan-3-ols of up to 8–10 units have been separated and quantitatively analyzed. These tannin sorghums are excellent antioxidants, which slow hydrolysis in foods, produce naturally dark-colored products and increase the dietary fiber levels of food products. Sorghums have high concentration of 3-deoxyanthocyanins (i.e. luteolinidin and apigenidin) that give stable pigments at high pH. Pigmented and tannin sorghum varieties have high antioxidant levels that are comparable to fruits and vegetables. Finger millet has tannins in some varieties that contain a red testa. There are limited data on the phenolic compounds in millets; only phenolic acids and flavones have been identified.     

Sorghum and millet phenols and antioxidants

Sorghum is a good source of phenolic compounds with a variety of genetically dependent types and levels including phenolic acids, flavonoids, and condensed tannins. Most sorghums do not contain condensed tannins, but all contain phenolic acids. Pigmented sorghums contain unique anthocyanins that could be potential food colorants. Some sorghums have a prominent pigmented testa that contains condensed tannins composed of flavan-3-ols with variable length. Flavan-3-ols of up to 8–10 units have been separated and quantitatively analyzed. These tannin sorghums are excellent antioxidants, which slow hydrolysis in foods, produce naturally dark-colored products and increase the dietary fiber levels of food products. Sorghums have high concentration of 3-deoxyanthocyanins (i.e. luteolinidin and apigenidin) that give stable pigments at high pH. Pigmented and tannin sorghum varieties have high antioxidant levels that are comparable to fruits and vegetables. Finger millet has tannins in some varieties that contain a red testa. There are limited data on the phenolic compounds in millets; only phenolic acids and flavones have been identified.     

加强闽台科技合作交流发展我省甘蔗业

概述了海峡两岸农业交流与合作的现状,提出了应该共同呼吁尽快实现两岸“三通”,开放农业生物技术图书期刊资料交流以及开放生物学科方面网络的思路,以便为农业交流与合作的顺畅开展打好基础,并寄希望能够就糖蔗、果蔗以及甘蔗笋等方面的研究与开发到台湾学习取经,开展学术交流或与台湾同行共同开展研究,为我省甘蔗业的发展作出贡献。     

种子加工、检验理论与技术现状及思考

种子加工及检验是种子向市场流通的关键，是商业化育种中赋予种子商品属性不可或缺的环节。种子加工、检验理论与技术的研究是完善种业产业链、实现规模化商业育种、夯实“育繁推一体化”种业科学的重要一环。中国的种业科学技术体系正在形成与完善之中，受制于行业发展水平，种子加工及检验理论与技术相对薄弱。本文回顾了种子加工及检验理论与技术研究发展历程，提出了完善中国种业科学发展的策略与建议。围绕种业发展的需要，在做好品种优质化繁育的基础上，分析种子加工及检验理论与技术的新方向和新需求，加强种业应用性研究，建立先进的种子质量检验体系，研制适合现代种业发展需求的种子加工设备，打造种子加工产业标准化生产体系，完善种业科学技术学科建设，促进种业产业持续健康发展。     

大豆几种常见病虫草害的诊断与防治

1大豆花叶病毒病 大豆病毒病（Soybean Mosaic Virus,SMV）是世界性病害之一。我国东北地区已鉴定的有5种,即大豆花叶病、顶枯病、蚕豆萎蔫病、南方菜豆花叶病、花生条纹病毒。其中大豆花叶病在全国大豆主要产区都有发生,十分常见。     

大豆根潜蝇及根腐病的发生与防治

近年来，随着大豆播种面积的增长，受病虫危害日趋严重。特别是大豆根潜蝇（又名根明）与根腐病共同发生危害，严重影响大豆的生产。综合防治技术主要手段是三年以上轮作，适时播种及种衣剂拌种等措施。     

Tuber and starch quality of wild and cultivated potato species and cultivars

Summary Between 1993 and 1998 205 different potato cultivars and 1220 accessions/genotypes of wild and cultivated potato species from the IPK Genebank Gatersleben were evaluated. Parameters interesting for starch isolation and especially for the use of starch were determined. Altogether, there was a higher variability in wild potato species than in cultivated potatoes for all characteristics investigated: dry matter content, starch content, protein content, amylose content and mean particle diameter of starch granules.     

Yield and quality of winter and spring triticales for forage and grain

In field experiments conducted over 2 years in Mediterranean conditions, five winter and five spring triticales were evaluated for forage and grain production in the same cropping season. The experiments had two treatments, namely harvesting for grain only, and dual-purpose forage and grain production. In the latter treatment, forage was cut when the first node was detectable (Zadoks' stage 31), without removing the apical meristems. Grain was harvested when ripe (Zadoks' stage 92) in both cut and uncut plots.
Environmental conditions affected grain production and protein content more than forage yield and quality. Winter triticales yielded about 43% more forage than spring types, but after forage removal the spring types yielded about 36% more grain than winter triticales.
Reductions in grain yield after clipping were more pronounced in winter (32%) than in spring (19%) types. Forage crude protein content was significantly higher in the spring types studied (24.6%) than in the winter types (23.5%), the opposite being true for fibre content (20.7 and 21.6% respectively). Grain crude protein content did not differ between grain and dual-purpose treatments, but was higher in the spring triticales (12.8%) than in the winter types (11.9%). There was more variability for the measured traits within the winter triticales studied than within the spring types.     

种子加工、检验理论与技术现状及思考

种子加工及检验是种子向市场流通的关键,是商业化育种中赋予种子商品属性不可或缺的环节。种子加工、检验理论与技术的研究是完善种业产业链、实现规模化商业育种、夯实"育繁推一体化"种业科学的重要一环。中国的种业科学技术体系正在形成与完善之中,受制于行业发展水平,种子加工及检验理论与技术相对薄弱。本文回顾了种子加工及检验理论与技术研究发展历程,提出了完善中国种业科学发展的策略与建议。围绕种业发展的需要,在做好品种优质化繁育的基础上,分析种子加工及检验理论与技术的新方向和新需求,加强种业应用性研究,建立先进的种子质量检验体系,研制适合现代种业发展需求的种子加工设备,打造种子加工产业标准化生产体系,完善种业科学技术学科建设,促进种业产业持续健康发展。