柠檬酸选择性降低烟气烟碱

研究滤嘴添加剂-柠檬酸对主流烟气的影响,实验结果表明:冷冻干燥法吸附效率明显高于注射添加,冷冻干燥法在不改变烟支物理状态的条件下,能降低烟气的pH值,相对选择性降低主流烟气的烟碱,5mg支/的添加量能降低烟气烟碱高达17.88%,对烟气中的游离烟碱降低更为有效(5mg支/的添加量能降低游离烟碱36.8%)。同时卷烟感官评价结果表明添加柠檬酸对卷烟烟气劲头、刺激、细腻程度、干燥感、杂气等都有一定的改善作用。     

茶叶茶多酚、咖啡碱提取及超滤-吸附综合分离纯化过程研究

介绍了采用三级错流提取茶叶有效成分茶多酚、咖啡碱的优化提取工艺。该工艺提取率高达９０％ 以上,其提取液经醋酸纤维素复合钛微孔体超滤膜初步纯化,可得到茶多酚含量大于４０％ 的部标三级品。并建立了茶叶水提取液超滤过程修正凝胶极化模型。超滤透过液经聚酰胺树脂吸附、８５％ 乙醇洗脱,得到茶多酚含量大于９０％ ,咖啡碱含量低于４％ 的部标茶多酚一级品。该工艺具有不另外添加物质、不使用有毒溶剂、工艺简单等特点。     

高效液相色谱法测定武夷岩茶中咖啡碱的条件探讨

文章主要探讨采用高效液相色谱仪(HPLC)测定武夷岩茶(以肉桂为例)中咖啡碱含量的影响因素和条件。采用C18(100 mm×4.6 mm)的色谱柱,以甲醇-水(60-40)为流动相,检测波长为275nm。实验结果表明:茶叶样品中咖啡碱含量与峰面积在标准曲线范围内线性良好,线性回归方程为Y=51.439X+37.053,R2=0.9999,另外在Mg O添加量为0.5 g,沸水浴中浸提时间为30 min时,测得咖啡碱含量的相对标准偏差为0.63%,加标回收率为92.0%~102.0%。该方法简单、快速、准确,且能应用于不同武夷岩茶品种中咖啡碱的检测。     

烟草pH值对烟气烟碱的影响

烟丝的pH值的升高,能提高烟气pH值与烟碱/焦油值,同时增加了烟气游离烟碱的含量,提高烟碱的转移率;此外对卷烟的感官品质也产生了一定的影响。     

13X分子筛对烟气中低分子醛酮的选择性吸附研究

为降低卷烟烟气中有害成分低分子醛酮化合物的含量和研究X型分子筛在卷烟减害中的应用,将13X型分子筛添加到卷烟嘴棒中,分析其对主流烟气中八种低分子醛酮化合物含量的影响。结果显示13X分子筛对低分子醛酮有明显的脱除作用。通过进一步研究13X分子筛对烟气中苯酚和苯并(α)芘的吸附作用,揭示了13X分子筛对低分子醛酮的选择性吸附与其因表面静电引力优先吸附极性物质的特性以及低分子醛酮的低熔沸点密切相关。烟气三项指标分析表明,13X分子筛对烟气中的焦油和烟碱含量影响不大,这有利于保持卷烟的香气。     

柠檬酸二乙酯选择性降低烟气烟碱

通过在卷烟滤嘴中添加柠檬酸二乙酯,在不改变烟支物理状态的条件下,能够有选择性降低主流烟气的烟碱,而基本不改变焦油等其他烟气常规成分。同时卷烟感官评价结果表明添加柠檬酸二乙酯对卷烟烟气劲头、刺激、细腻程度、干燥感、杂气等都有一定的改善作用。     

烟碱快速分析法的研究

研究了甲基橙与烟碱的显色反应，并将其应用于直接测定烟气中的烟碱含量，获得较为满意效果。     

茶叶和饮料中咖啡碱的测定

<正> 咖啡碱具有中枢神经兴奋作用。在多种食品中都含有咖啡碱,它是茶叶、饮料的重要成分。咖啡碱的含量是这类食品的一项重要质量控制指标。对其含量分析一般采用容量法,此法操作繁琐,消耗溶剂量大。近来有文献报道,采用光度法和液相色谱法测定咖     

烟碱快速分析法的研究

研究了甲基橙与烟碱的显色反应，并将其应用于直接测定烟气中的烟碱含量，获得较为满意效果。     

超高压处理对普洱茶理化和感官品质影响的研究

普洱茶是我国特有的一类后发酵茶。本文以100~500 MPa的条件对普洱生茶进行了超高压处理,研究了处理前后茶叶中茶多酚、咖啡碱、氨基酸含量等理化品质及香气、滋味、汤色等感官品质的变化,并采用气质联用分析了处理前后茶叶中香气成分的变化规律。结果表明:经超高压处理后,茶叶中茶多酚、咖啡碱、氨基酸含量等理化指标有所降低,而香气、滋味、汤色等感官评分有所提升;对感官品质有贡献的萜烯类、醇类、醛类、内酯等香气成分均有所增加。     

发酵对普洱茶中游离咖啡因含量的影响

目的探讨普洱茶发酵过程中咖啡因的存在形式及游离咖啡因含量的变化,为监测茶叶发酵程度,控制茶品质量提供依据。方法应用低pH沉淀结合高效液相色谱法(HPLC)检测普洱茶发酵全程中6个主要发酵阶段[一翻、二翻、三翻、四翻、五翻样品和出堆样品(熟茶)]样品的游离咖啡因和结合咖啡因含量。结果普洱茶发酵过程中,游离咖啡因含量逐渐降低,从一翻样品的(2.555±0.104)%降至出堆样品的(1.878±0.049)%,超过1/4的咖啡因与茶中的其他组分相结合,形成结合咖啡因。结合咖啡因的含量不断增加,四～五翻期间增幅最大,从0.084%增至0.647%;出堆样品中结合咖啡因的含量最高,为0.703%。结论发酵过程中,普洱茶中的游离咖啡因含量逐渐降低。本实验为监测茶叶发酵程度,控制茶品质量提供了依据。     

模拟日常饮茶方式浸泡茶水中咖啡因测定

目的:测量都匀毛尖、湄潭翠芽、凤冈锌硒茶所泡茶水中的咖啡因,为人们合理购茶、饮茶提供理论依据。方法:采用模拟日常饮茶方式浸泡茶叶,通过超高效液相色谱法测定茶水中的咖啡因。结果:湄潭翠芽所泡茶水中咖啡因含量最高,都匀毛尖次之,凤冈锌硒茶最低。浸泡时间对茶水中咖啡因的含量影响不大;浸泡水温越高,茶水中咖啡因含量越高;浸泡次数越多,茶水中咖啡因含量越低。结论:建立的超高效液相色谱法测定茶水中咖啡因的方法快速可靠。茶水中咖啡因含量受茶叶品牌、浸泡水温等因素影响。     

水在超临界CO2脱除绿茶中咖啡因的作用研究

采用不同的茶叶预处理方式,并在不同的萃取条件下,用超临界CO2对茶叶进行脱除咖啡因试验,以考察茶叶含水量与咖啡因萃取率的关系。指出了水对咖啡因萃取的3方面影响,即脱附茶叶基质上的咖啡因、使茶叶膨胀而改善咖啡因的传质状况及抑制咖啡因从水相进入超临界流体相。同时说明了此3者对萃取过程的影响机理。     

Preparation of Cold Brew Tea by Explosion Puffing Drying at Variable Temperature and Pressure

Cold brew tea was prepared using explosion puffing drying at variable temperature and pressure. The influences of moisture content of predried tea leaves, freezing pretreatment times at ?18°C, and puffing temperature on water extracts content of cold brew tea were studied according to the orthogonal experiments of processing of cold brew tea based on single factors. The biochemistry ingredients of cold brew tea and hot air–dried green tea were determined and compared. The optimum processing conditions of cold brew tea were obtained as follows: predried tea leaf moisture content 50%, freezing pretreatment three times, puffing temperature 105°C. Under these optimized processing conditions, cold brew tea was obtained. When cold brew tea was soaked in cold water for 30 min at 20°C, the water extracts content, caffeine, tea polyphenols, and free amino acids of cold brew tea reached 18.21, 0.88, 11.86, and 1.02%, respectively. High-performance liquid chromatography (HPLC) analysis showed that the amount of tea catechins in cold brew tea and hot air–dried green tea were 11.74 and 11.47%, respectively. The caffeine in cold brew tea was 3.06%, equal to that in hot air–dried green tea. Experimental results showed that biochemistry ingredients of cold brew tea prepared by explosion puffing drying at variable temperature and pressure difference were easy to extract by low-temperature water. This research provides theory and technical support for industrialized production of cold brew tea.     

普洱生茶和熟茶中咖啡因含量测试

用热水浸提法分别提取15个普洱生茶样品和15个普洱熟茶样品中的咖啡因,采用紫外分光光度法,以咖啡因为标准品,蒸馏水为空白对照,于274 nm波长处分别测定对照品和供试品溶液的吸光度,按标准曲线计算咖啡因含量。回归方程为y=47.945x+0.0015,R2=0.9999。15个普洱生茶样品中的咖啡因平均含量4.29%,15个普洱熟茶样品中咖啡因平均含量为3.31%。     

Effect of ethanol content on supercritical carbon dioxide extraction of caffeine from tea stalk and fiber wastes

This study presents the effect of ethanol content on supercritical carbon dioxide extraction of caffeine from tea plant wastes. Tea stalk and fiber wastes of Turkish tea plants that have no economical value were evaluated as raw material throughout the caffeine extraction experiments. These wastes were supplied from tea factory marked “Çaykur” in the east blacksea region. They were separately ground, sieved and dried at 105 °C temperature in an oven. Parameters affecting caffeine leaching from tea wastes were determined to be, ethanol flow rate, extraction time, extraction temperature, carbon dioxide flow rate, process pressure and particle size. The maximum yield of caffeine from tea stalk wastes and fiber wastes were 14.95 mg/g tea stalk and 18.92 mg/g tea fiber, respectively. When the supercritical extraction conditions used of ethanol as cosolvent have been compared with the conditions of used only carbon dioxide, approximately the same yield has been reached at 2 h extraction period instead of 7 h. Beside of saving of the time and the amount of carbon dioxide, the supercritical extraction yield with cosolvent increase had been recorded as 62.5% and 63.1%, respectively, in comparison with the chloroform extraction as conventional method of tea stalk and fiber wastes.     

Particle-Gas Equilibria of Ammonia and Nicotine in Mainstream Cigarette Smoke

The particle-gas equilibria of ammonia and nicotine in mainstream cigarette smoke have been studied by diffusion denuder collection. The surface deposition rate of nicotine is observed to decrease as the smoke traverses the denuder, and this effect is attributed to a changing particle nicotine vapor pressure driven by the measured rapid loss of volatile ammonia from the particles, an interpretation that differs from that of prior studies. The rapid ammonia deposition is observed to be complete at a length-to-flow rate ratio of 28 s/cm 2 for an American blended cigarette, and ～38% of the total ammonia analyzed in the collected smoke appears to be nonvolatile in the aerosol, possibly bound in the particles by reaction with acids. Fitting of a theoretical model that predicts the rapid ammonia loss and changing nicotine vapor pressure to the measurements predicts that the nicotine vapor pressure over the particles in fresh smoke is about 6% of the pure component nicotine value, and the ammonia vapor pressure over the smoke particulate is considerably less than that predicted by its aqueous Henry's law coefficient. Dilution of mainstream smoke enhanced the fractional deposition of both ammonia and nicotine in the denuder tubes and provided a means to estimate the nonvolatile ammonia fraction, which varied considerably in cigarettes made with different tobacco types. Among the different tobacco type cigarettes, smoke ammonia concentration, "smoke pH," and smoke nicotine-to-particulate ratio varied with ammonia and nicotine deposition from diluted smoke when extreme values for an all burley tobacco cigarette were included in the analysis, but no trends were apparent when only the more typical range of the other cigarettes was considered.     

Partition Coefficients of Alkaloids in Biphasic Ionic-Liquid-Aqueous Systems and their Dependence on the Hofmeister Series

The aim of this work is to test the potential of hydrophobic phosphonium-based ionic liquids for the extraction of caffeine and nicotine from aqueous phases through the determination of the alkaloids' partition coefficients. It was found that the caffeine partitioning for the ionic-liquid-rich phase increases with the ionic liquid hydrogen-bonding accepting capability (or water content), while for nicotine a nearly opposite behavior was observed. In addition, both the influence of the ionic concentration of the aqueous solution (ranging from 0.0 mol · kg^?1 to 3.0 mol · kg^?1), and the salt nature (with K- and Na-based salts), in the partitioning of caffeine for the ionic-liquid-rich phase were investigated. The influence of the inorganic salt nature in the alkaloid partitioning for the ionic-liquid-rich phase closely follows the Hofmeister series.     

卷烟主流烟气TPM及其pH与烟气烟碱量的关系

研究了16种不同牌号卷烟主流烟气总粒相物(TPM)及其pH与其烟气烟碱量的关系。结果表明,总粒相物与烟气烟碱量之间的关联性比较显著,烟气烟碱量较大的牌号,其烟气总粒相物也较大。该研究对于人们的吸食健康有一定的指导意义。     

茶多酚的制备新方法

阐述了茶多酚制备的传统方法及存在的问题。报道了运用超临界CO2 萃取技术与溶剂萃取相结合生产茶多酚的方法。实验结果表明 :运用超临界CO2 萃取技术与溶剂萃取相结合的方法生产的茶多酚 ,其含量可大于 90 % ,咖啡因含量小于 2 % ,收率大于 9% (以茶叶计 ) ,残留溶剂为零