大豆油对绿茶汤中咖啡因脱除作用的研究

通过大豆油脱除绿茶汤中咖啡因的试验,对温度、萃取比例、萃取次数等影响咖啡因脱除率的因素进行研究,提出了大豆油脱除绿茶汤中咖啡因的合适萃取条件。     

化学计量学在茶叶质量控制中的应用

客观质量评定及分级标准化对茶叶来说,是亟待解决的问题,化学计量学的引入,对大量茶叶样品的大量品质成分数据进行多元处理,可快速全面的将茶叶的化学信息进行鉴别归类,弥补传统感官审评受主观因素影响较大的缺陷。本文综述了几种常用的化学计量学模式识别方法在茶叶品质分级、真伪鉴别以及产地鉴别中的重要进展,为促进茶叶标准化加工、品质智能化识别以及产地溯源技术的发展提供理论参考。     

3种茶提取物对MCF-7细胞增殖、凋亡的影响及其与蛋白激酶B的相关性

目的 探讨红茶、绿茶及普洱茶提取物对人乳腺癌细胞MCF-7增殖、凋亡的影响及其与蛋白激酶B(Protein ki-nase B,PKB)的相关性。方法用不同浓度的3种茶提取物处理MCF-7细胞不同时间,MTT法检测其对MCF-7细胞增殖的影响;Annexin V-FITC/PI双染流式细胞术检测其对细胞凋亡的影响;实时定量PCR检测细胞PKB基因mRNA的转录水平。结果 3种茶提取物对MCF-7细胞的增殖均具有明显的抑制作用,且呈时间、剂量依赖性;3种茶提取物处理的细胞早期凋亡率均高于未处理细胞,PKB基因mRNA的表达量明显降低。结论 3种茶提取物均含有可以抑制PKB转录活性的天然成分,并可诱导MCF-7细胞凋亡;其中绿茶诱导MCF-7细胞凋亡效果最明显。     

保香低温速溶红茶粉的研发

为了解决速溶茶粉的滋味淡、香气低、冷溶性差等问题,该试验以红茶为原料,采用高压脉冲电场（Pulsed Electric Field,PEF）技术辅助提取和杀菌,并结合冷冻浓缩和真空冷冻干燥联合真空吸附干燥法生产速溶红茶粉,使得整个加工工艺都在低温状态下完成。试验结果表明,高压脉冲电场技术有助于提高红茶的提取率,冷冻浓缩和高压脉冲电场杀菌能够有效保持茶汤的色、香、味;真空冷冻干燥联合真空吸附干燥后所得的速溶红茶粉的得率为22.7%,且其冷溶性高,滋味鲜浓而醇厚,香气高而纯正,汤色红艳明亮,无沉淀。     

高效液相色谱法测定五种茶叶中咖啡因含量

目的：采用高效液相色谱法测定了5种茶叶中咖啡因的含量。方法：采用Phenonm enxC18（4.6 mm×250 mm,5μm）反相色谱柱,流动相CH3OH H2O=5.5 4.5,流速1.0（mL·m in^-1）,检测波长为272 nm,柱温为35℃,在所选条件下,样品中待测组分与其它组分分离良好（R〉1.5）,通过重复性实验和加标回收实验,验证了方法的稳定性和可靠性。在本实验范围内各组分的峰面积和浓度之间具有良好的线性关系,r^2=0.999 9,5种茶叶的咖啡因回收率97.48%～107.73%,RSD=2.6%～3.0%。     

HPLC-TOF/MS测定茶籽粕中的茶皂素

本文利用高效液相色谱-电喷雾-飞行时间质谱（HPLC-ESI-TOF/MS）在负离子模式下成功检测了茶籽粕中提取的茶皂素。高效液相色谱分析茶皂素超纯品得到5个主要皂甙峰,出峰时间分别为4.01、19.52 、27.74、29.23 和34.01 min,各吸收峰峰形对称,茶皂素组分能够较好分离。不同浓度茶皂素的定量曲线表明5个峰的峰面积与茶皂素含量的线性回归方程相关系数r值均在0.99以上。ESI-TOF/MS质谱分析结果表明5个组分分别含有2-5种五环三萜类皂甙, 合计18种。该法有较高的精确性,可用于茶皂素的定性、定量分析。     

Antibacterial Action of Haw Pectic Oligosaccharides

Haw pectic oligosaccharides, lactic acid, sodium lactate, and tea polyphenol showed dose and pH dependent antibacterial activity against E. coli. The activity of haw pectic oligosaccharides could be enhanced by combination with lactic acid, sodium lactate, or tea polyphenol. However, combination of haw pectic oligosaccharides with nisin resulted in no significant enhancement of antibacterial activity against E. coli. These results revealed that haw pectic oligosaccharides is valuable as a food preservative, and lactic acid or sodium lactate could be used to enhance its antibacterial activity, allowing for further improvement in its efficiency, likely leading to a reduction in the dosage necessary for food preservation.     

石墨炉原子吸收光谱法测定茶叶中铅时消解方法的选择

用石墨炉原子吸收光谱法测定5种不同方法消解的茶叶中铅的含量,发现不同的消解方法对茶叶中微量元素铅的测定结果影响很大,从中也探索出测量茶叶中铅最低损耗的最佳消解条件,就是采用硝酸-高氯酸微波消解方式。方法灵敏度高,加标回收率为97.94%~101.86%,适合于茶叶中铅的日常检测。     

Adsorption Characteristics of Congo Red from Aqueous Solution onto Tea Waste

The feasibility of using tea waste (TW) as a low-cost adsorbent for the adsorption of an anionic dye (Congo red) from aqueous solution has been investigated. Adsorption in a batch process was conducted to study the effect of adsorbent dosage, initial dye concentration, contact time, pH, and temperature. The experimental data were analyzed by the Langmuir, Freundlich, and Temkin models. The adsorption system was best described by the Langmuir isotherm (R ² > 0.99). Adsorption kinetics followed a pseudo-second-order model (R ² > 0.99). The effect of mechanical treatment (vibratory mill) was also studied. The experimental results showed that using this physical treatment leads to an increase in the adsorption capacity of TW from 32.26 to 43.48 mg/g. Thermodynamic analyses revealed that the adsorption of Congo red on TW was endothermic and spontaneous in nature. The results indicated that TW can be employed as a potential low-cost adsorbent for the removal of Congo red from aqueous solution.     

茶多酚与VC对猪油乳化体系协同抗氧化性研究

研究了茶多酚与ＶＣ在猪油乳化体系中的协同抗氧化性,初步探讨了协同效应的条件和内在机理。结果表明在猪油乳化体系中,ＴＰ与ＶＣ具有显著的协同抗氧化作用。高浓度的ＶＣ在低浓度ＴＰ,表现出较强的抗氧化协同效应,适当的ＴＰ浓度与ＶＣ组合时,表现出稳定而较强的协同抗氧化效能。当ＴＰ浓度上升到一定水平后,协同抗氧化性消失,ＴＰ达到抗氧化－助氧化作用的平衡浓度;此平衡浓度主要受ＶＣ浓度的影响。