从竹叶中同步提取多糖、茶多酚和黄酮的研究

研究高压脉冲电场法同步提取竹叶中黄酮、茶多酚和多糖的工艺。以竹叶为原料,在电场强度、脉冲数、提取介质pH和料液比4个单因素实验的基础上,采用L9(34)正交实验确定最优化工艺。结果表明,采用高压脉冲电场法进行同步提取,竹叶黄酮、茶多酚和多糖提取率分别可达到2.48%,0.93%和3.54%,竹叶黄酮与多糖的提取率比传统方法提高了25%以上,但茶多酚的提取率略有降低。该工艺可同步有效地从竹叶中提取黄酮、茶多酚和多糖,对于综合开发竹叶活性成分具有指导意义。     

雷竹叶多糖与黄酮的联合提取工艺设计

设计了联合提取多糖与黄酮的新工艺,通过红外光谱鉴定了提取物.竹叶中粗多糖的含量为8.79%,黄酮的含量为26.33 mg/g(竹叶粉).而精制后多糖(BP1)占粗多糖的37.5%,均与单一提取法的文献报道值接近.     

竹叶中茶多酚的提取及其抗氧化性研究

探讨用超声技术从竹叶中提取茶多酚的最优工艺条件,并对茶多酚的抗氧化性进行研究。以茶多酚的产率为考察指标,通过单因素试验和正交试验确定从竹叶中超声提取茶多酚的适宜工艺条件：超声功率为70W,浸提温度75℃,超声时间40mn,料液比1：20,乙醇体积分数75％,此条件下茶多酚提取产率为0．624300。以Fenton反应、DPPH法检测其清除自由基活性,结果表明,竹叶中茶多酚具有较强的清除羟基自由基的能力,是一种很好的天然抗氧剂。     

雷竹叶芳香油的提取及其化学成分的研究

以新鲜和干雷竹叶为材料,经乙醚浸提、蒸馏并精制,获得了具有清香味的淡黄色透明芳香油液。经气相色谱仪对其组分和含量进行测定,给出了可靠结果,对应的干雷竹叶和鲜雷竹叶的可测组分分别为23种和18种,并发现干竹叶比鲜竹叶不仅组分的数量和种类多,且增加了3种复杂酮类及10种新组分。这些都为雷竹叶芳香油的开发及利用提供了可靠依据。     

茶多酚的超滤分离及其在化妆品中的应用

优化了超滤分离竹叶提取液中茶多酚(TP)的工艺条件,并进行了茶多酚在化妆品中应用的功能评价。通过正交试验得到超滤分离的最优工艺为:操作温度35℃,压力0.10 MPa,原料液质量浓度为0.21 mg.mL-1,pH=7。所得产品经生物活性试验研究表明,茶多酚对酪氨酸酶活性有明显的抑制作用和较强的清除DPPH自由基、羟自由基和超氧阴离子的能力,美白乳液中添加w(TP)=1.5%就能明显降低皮肤内黑色素含量。茶多酚可作为化妆品中的天然添加剂。     

竹叶中叶绿素提取工艺研究

竹叶中叶绿素提取工艺研究０引言天然叶绿素多以蚕砂、雏菊、菠菜、绿藻为原料进行提取精制。叶绿素不仅是良好的天然食品色素，而且在医药上具有广泛的用途。我国现有竹林总面积为五千余万亩，竹子约３００亿株［１］。竹叶表面绿色，背面浅绿色，竹叶不但叶绿素含量高（...     

肉桂原花青素的片段化研究

采用食物来源的茶多酚为亲核试剂对肉桂中原花青素多聚体(PPC)进行片段化反应,采用大孔吸附树脂HP-20对片段化反应产物进行分级处理,使低聚体从片段化反应产物中分离出来。以反应后低聚体含量和低聚体中原花青素含量为考察指标,通过单因素试验、正交试验考察了片段化反应时间、反应温度、盐酸体积分数和多聚体与茶多酚物料比对反应的影响。结果表明,各因素对反应的影响次序为:盐酸体积分数 > 多聚体与茶多酚物料比 > 反应温度 > 反应时间,片段化反应最佳条件为:反应温度为50 ℃、反应时间为60 min、盐酸体积分数为1%、多聚体与茶多酚物料比为1:1,在此条件下,得到片段化反应后低聚体含量为65.26%,低聚体中原花青素含量为75.28%。     

不同种类茶叶中茶多酚含量的测定

采用离子沉淀法,对不同种类茶叶中的茶多酚含量进行测定。分别考察了不同酸度、浸提温度及浸提时间对测定茶多酚含量的影响,确定以3价铁离子作为沉淀剂时,浸提时间为30 min,料液比低于或等于1∶15,pH为8或9,借助分光光度法测得不同品种茶叶中茶多酚的含量。结果表明:花茶的茶多酚提取率为1.63%,绿茶的茶多酚提取率为5.27%,红茶的茶多酚提取率为1.37%。     

从箬竹叶中提取茶多酚的研究

研究了从箬竹叶中提取茶多酚的工艺;探讨了茶多酚的提取方法及相应的提取条件;利用UV 9200型分光光度计对提取产物茶多酚含量进行测定。通过对溶剂选择及用量、提取时间、提取温度等影响因素的研究,确定了茶多酚提取的最适宜的工艺条件:乙醇浓度65%,溶剂用量与箬竹叶用量之比为6～7倍(mL/g),提取温度55℃,萃取次数3～4次,提取时间4～5h,在此条件下茶多酚得率为0.68%。     

4,4'-二羟甲基联苯的合成工艺研究

以4,4'-二氯甲基联苯为原料,经酯化、水解反应合成了4,4'-二羟甲基联苯,其结构经1H NMR及MS(APCI)表征。分别对酯化物中间体及产物的合成方法进行了探索,结果表明,在优化合成路线下,目标产物的总收率为94%,且产物不经精制提纯含量即达到99%以上。     

Antioxidant activity of tea extracts in lipids and correlation with polyphenol content

The present study examined the antioxidative activity of water and ethanol extracts of green and black tea leaves against the oxidation of heated sunflower oil and lard. Oxidation was conducted at 110 °C in the Rancimat test. Total polyphenols and catechin contents in tea extracts were measured. The research showed that the total polyphenol content in green and black tea leaves was 205.2 and 148.7 mg/g, respectively. In tea leaves extracts, it ranged between 245.9 mg/g and 837.7 mg/g and depended on the extraction solvent and the kind of tea used (p <0.001). The highest polyphenol content was observed in samples extracted with 95% ethanol, lower contents were found with the use of water. Results showed that the highest antioxidant activity, measured as an induction period, with 1000 ppm green tea ethanol extract, was comparable to á‐tocopherol activity in sunflower oil. In lard, the longest induction period was measured with 500 and 1000 ppm of green tea ethanol extract. Other tea extract concentrations were significantly less active. Statistical analysis of the tea extract antioxidant activity in lipids in the Rancimat test showed an essential influence of the catechin contents. Further statistical analysis also showed an influence of (?)‐epicatechin gallate (ECG), (?)‐epicatechin (EC), and (+)‐catechin (C) contents in the tea extracts on the antioxidant activity in lipids. It was stated that the antioxidant activity was higher in tea extracts containing high levels of ECG, EC, and C.     

茶树花中功能性成分的提取与分析研究

采用分光光度法测定茶多酚、茶多糖等功能性成分含量;用高效液相色谱法测定茶多酚中儿茶素组成成分,离子色谱积分安培法测定多糖中单糖的组成成分。实验表明:茶树花中含茶多酚含量为3.62%~4.48%,总糖为16.15%~23.25%,其中茶多糖为1.60%~1.65%,茶氨酸为3.92%~5.03%,黄酮为0.141%~0.162%。分析结果表明茶树花中功能性成分与茶叶中的成分相似,为进一步开发利用茶树花资源提供理论依据。     

Antioxidant Activities of Free and Liposome-Encapsulated Green tea extracts on canola oil oxidation stability

In the present study, green tea extract was encapsulated in liposomes based on the Mozafari method (with no organic solvents) and characterized for its physicochemical properties (encapsulation efficiency, particle size, and Z-potential). Encapsulation efficiency, particles size, and Z-potential were determined to be 51.34, 419 nm, and -57 mV, respectively. Total polyphenol content of the green tea by Folin-Ciocalteu's phenol reagent was measured as 164.2 mg gallic acid/g extract. Free radical scavenging activities of free and liposomal extracts were 90.6 and 93.4%, respectively, using the DPPH method. Antioxidant activity of the ethanolic extract of green tea in free and liposomal forms with concentrations of 200, 600, and 1000 mg L⁻¹ were assessed on oxidative stability of the canola oil at 60 °C for 0, 4, 8, 12, 16, 20, 24, 28, and 32 days. Results were compared to results of synthetic antioxidant butylated hydroxytoluene at 200 mg L⁻¹. To assess antioxidant activity on canola oil stability, peroxide, thiobarbitoric acid, and anisidine values were assessed as well as the total oxidation value and rancimat test. Results showed that the liposomal green tea extract was more effective than the free extract. Furthermore, a 600 mg L⁻¹ concentration of the green tea extract showed a significant antioxidant activity, compared to other extract concentrations. Increasing storage time and various concentrations of the ethanolic green tea extracts included significant effects on canola oil stability (P ≤ 0.05). Results demonstrated that the green tea extract could be used as an effective antioxidant. Free and liposomal extract (at 600 mg L⁻¹) resulted in stronger functionality than the synthetic antioxidant butylated hydroxytoluene.     

超临界流体萃取普洱茶多酚的可行性初探

本文从茶多酚系列产品在食品和医药工业的应用和市场前景出发 ,结合云南普洱茶的资源情况 ,介绍了茶多酚提取的新方法———超临界流体萃取法的原理、工艺流程、主要设备等。并对 150t/a茶多酚系列产品的生产装置进行了经济技术分析和环境影响评价。     

负载茶多酚的三元共混膜液与膜性能分析

将不同质量分数的活性成分茶多酚加入到壳聚糖/玉米醇溶蛋白共混膜液中，采用溶剂浇铸法制备得到一种三元共混膜。分析茶多酚对壳聚糖/玉米醇溶蛋白膜液静态和动态流变学特性、粒径分布以及凝胶强度的影响；测定三元共混膜的机械性能和阻隔性能；同时对共混膜进行形貌、红外、晶体学和热力学分析。结果表明：茶多酚与成膜基质之间的交互作用使膜液中产生了高度纠缠网络结构，有利于均匀稳定共混膜的形成；负载适量茶多酚对膜性能具有良好的改善作用，当茶多酚负载量为1%时，膜材料具有最佳的抗拉强度10.966 Mpa；SEM和XRD结果显示茶多酚与壳聚糖、玉米醇溶蛋白之间发生了强烈的相互作用，具有良好的相容性；FT-IR图谱显示茶多酚与成膜基质之间产生了氢键相互作用；通过热力学分析发现负载茶多酚质量分数为0.5%和2%时，共混膜具有较高的热稳定性。     

Changes of constituents and activity to apoptosis and cell cycle during fermentation of tea

Tea is believed to be beneficial for health, and the effects of the fermentation process on its contributions to apoptosis and cell cycle arrest of gastric cancer cells have not been completely investigated. In this study, the chemical components in green tea, black tea and pu-erh tea aqueous extracts were analyzed and compared. The polysaccharide and caffeine levels were substantially higher in the fermented black tea and pu-erh tea, while the polyphenol level was higher in the unfermented green tea. Hence, a treatment of tea aqueous extract and the components, which are emerging as promising anticancer agents, were pursued to determine whether this treatment could lead to enhance apoptosis and cell cycle arrest. In the human gastric cancer cell line SGC-7901, the cell viability and flow cytometry analysis for apoptotic cells indicated effects in a dose-dependent inhibition manner for the three tea treatment groups. The apoptosis rates were found to be elevated after 48 h of treatment with 31.2, 125, and 500 μg/mL of green tea extract, the higher catechins content may be involved in the mechanism. Cell cycle was arrested in S phase in the fermented black tea and pu-erh tea, and the populations were significantly decreased in G2/M phases, possibly due to the oxidation of tea polyphenols, which causes an increase of theabrownins. CCC-HEL-1 normal cells were not sensitive to tea extract. These findings suggest that the fermentation process causes changes of the compounds which might be involved in the changes of cell proliferation inhibition, apoptosis induction and cell cycle arrest.     

PEG/（NH4）2SO4双水相萃取分离茶氨酸的研究

采用聚乙二醇(PEG)/(NH4)2SO4双水相体系萃取分离生产茶多酚所得废液中的茶氨酸,考察了PEG分子量与含量、硫酸铵含量、pH、温度、加盐(KCl、KBr、KI)、茶氨酸含量对双水相及萃取分离茶氨酸的影响。结果表明,PEG/(NH4)2SO4双水相萃取分离茶氨酸的适宜条件是:PEG平均分子量为4 000,质量分数为10%,硫酸铵质量分数为15%,pH约为6,30℃。在此条件下,茶氨酸的分配系数K1=0.16,蛋白质的分配系数K2=0.28,糖类的分配系数K3=9.8,茶氨酸在下相的萃取率为89.5%,可以将茶多酚废液中的茶氨酸与糖类及其他有颜色的杂质分开。     

茶叶中茶多酚的提取及分析检测

研究了茶叶中茶多酚的提取,并对所提取的荼多酚进行分析及检测.以茶叶为原料,水作为浸提溶剂,通过改变溶剂用量、浸提温度、浸提时间、乙酸乙酯用量4个因素提高茶多酚的提取率,并优化茶多酚的提取工艺条件.结果表明,最佳提取工艺条件为溶剂用量(固液比)1∶20,浸提温度85℃,浸提时间40 min,乙酸乙酯用量85 mL.在优化...     

微波干燥和热风干燥对金萱茶叶品质影响

将微波干燥和热风干燥应用于新鲜金萱茶叶的干燥,在3个不同的微波功率（350 W,470 W,800 W）和4个不同的空气温度（70 ℃,80 ℃,90 ℃,100 ℃）下,研究了干燥参数即微波功率或温度对干燥时间、失水量的影响,同时还考察了茶叶中茶多酚总量和儿茶素含量的变化、干茶叶的复水性。实验得出,与热风干燥相比,微波干燥的时间缩短了76%～95%,而且干燥后的茶叶有很好的复水性,但干燥后茶多酚总量少于热风干燥;同时随着功率增加,微波干燥时间由11 min降为6 min,随着温度升高,热风干燥时间由127 min缩短为45 min。这两种方法的茶叶干燥动力学模型均满足Page’s半经验公式。     

红茶氨基酸、茶多酚、咖啡因的低强度多频超声浸取特性

用DPS系统建立了包括温度、茶水质量比、时间、超声强度和超声频率(28 kHz和40 kHz)等因素的均匀设计实验方案,探索水为溶剂,低强度(低于0.6 W.cm-2)单频、双频复合和双频交变超声浸取红茶氨基酸、茶多酚、咖啡因的浸取特性;以质量浓度、浸取率为指标,用偏最小二乘法处理实验数据,以标准化回归系数评价各因素的影响程度。结果表明,与单频超声场相比,双频超声场降低了超声作用强度54%~67%,提高了温度、茶水质量比等其他单因素作用强度34%~143%;双频交变超声场的这种作用最强。双频交变超声场降低了除温度-茶水质量比之外所有双因素的作用强度12%~75%;而双频复合超声场提高了与超声强度有关的双因素作用强度19%~1 350%,降低了与超声场无关的双因素作用强度47%~75%。90℃0.3 W.cm-23种超声场浸取5 m in,红茶3种成分浸取特性有明显差异,双频复合超声浸取氨基酸的质量浓度和浸取率最高(分别为369.4mg.L-1和55.0%);双频交变浸取茶多酚、咖啡因最好,质量浓度分别为11.4、2 749.52 mg.L-1,浸取率为39.8%、49.8%,单频超声浸取效果最差。