茶树叶片中茶皂素提取工艺优化

以夏季茶树老叶为原料,利用乙醇水溶液提取茶皂素,考察液料比、乙醇体积分数、浸提温度和浸提时间对粗提物中茶皂素含量及茶叶中茶皂素得率的影响。单因素试验结果表明,液料比10︰1(mL/g)、乙醇体积分数70%、浸提温度60℃和浸提时间1.5 h时为宜。通过正交试验确定了茶皂素提取的最佳工艺:液料比20︰1(mL/g)、乙醇体积分数60%、浸提温度70℃、浸提时间2 h。试验结果为夏秋茶资源中茶皂素的提取提供参考。     

茶多糖的分离纯化及其抗凝血活性

为了研究茶多糖不同组分对抗凝血活性的影响,通过水提醇沉的方法对茶多糖进行提取,经聚酰胺柱脱色、脱蛋白,采用离子交换柱DEAE Sepharose CL-6B对多糖进行分离纯化,用高效凝胶渗透色谱测定其分子量,并对多糖组分抗凝血活性进行了研究。结果表明:聚酰胺法脱色、脱蛋白效果较好,脱色率、蛋白去除率和多糖保留率分别为75.1%、91.2%和79.2%;经纯化后得到4个组分,分别为TPS-1、TPS-2、TPS-3和TPS-4;HPGPC法测定TPS-1、TPS-2和TPS-3分子量分别为20760、24230和250643,为均一多糖,TPS-4含两个组分,其分子量分别为689 113和4 150,为非均一多糖。体外抗凝血实验显示TPS-4能延长活化部分凝血活酶时间(APTT)和凝血酶时间(TT),说明是通过内源性途径来影响凝血的。     

Effect of Gibberellins on Chemical Composition and Quality of Tea ( Camellia sinensisL)

The effect of gibberellins on tea leaf chemical composition and quality was investigated. The results showed that application of gibberellins was beneficial to green tea quality. Content of amino acids increased by 9·8% and that of vitamin C by 17·8% and tea catechins index increased by 12·9%. The content of tea polyphenols and ratio of tea polyphenols to amino acids decreased by 9·9% and 11·5%, respectively. Differences of all the indicators were statistically significant (P<0·05). Quality scores of the treated leaf increased significantly (P<0·05). It was also revealed that tea plant response to gibberellins was dependent not only on genetics, but also on shoot development stage.     

营养盐加量对酵母发酵的影响初探

研究了玉米淀粉浆在不同添加比例的营养盐1#、2#、3#、4#、5#液化、糖化,在发酵22h、46h、60h进行发酵试验对比,将能使酵母生长状态好,酵母数多、出芽率高、产酒率高的样品应用到生产中。     

Effect of extraction temperature on cream and extractability of black tea [Camellia sinensis (L.) O. Kuntze]

Summary Tea cream and haze in black tea infusions increased with the rise in the tea extraction temperature. The temperature at which substances involved in cream and haze formation began to be extensively extracted into the tea infusion was between 50 and 60 °C. The tea cream particle volume concentration in infusions extracted at 50 °C or below formed less tea cream particles, and their particle sizes were larger and more heterogeneous than those extracted at 60 °C and second infusions extracted at 90 °C from the residual leaves that were previously extracted at 40–50 °C. High‐performance liquid chromatography confirmed that constituents with pyrogallol groups are involved in tea creaming, and the effect of caffeine on tea cream and haze depends on whether these constituents are sufficiently present. The extractability of tea increased with the rise in extraction temperature. Two‐stage extraction of tea in ready‐to‐drink tea processing and its effects on colorimetric indicators were also examined.     

茶叶籽中总黄酮的提取及结构的初步鉴定

研究茶叶籽中总黄酮的提取工艺,在单因素实验基础上,选取液料比、提取温度和乙醇体积分数3个影响因素,以总黄酮含量为评价指标,通过Box-Benhnken的中心组合设计原理和响应面分析法优化提取工艺,确定最佳提取条件为:液料比26∶1(mL∶g),乙醇体积分数58%,提取温度82℃,提取时间2h,茶叶籽中总黄酮含量为11.174mg/g。通过颜色反应和紫外光谱特征,初步鉴定茶叶籽黄酮为二氢黄酮类化合物。     

Effect of Maofeng tea processing on leaf trichomes of tea (Camellia sinensis L)

Scanning electron microscopy was used to investigate the ultrastructure of trichomes on Maofeng, a special Chinese green tea. The trichomes were cylindrical in appearance with a length of 0.6–1 mm, wall thickness of 0.2–0.3 μm and a mid-point diameter of 9–10 μm. The angles between the trichomes and the leaf under-surface were below 30° in Maofeng tea though they were 45–75° in fresh green leaf. The trichome wall consisted mainly of fibre and its outer-surface was unevenly covered with waxy substances and striped. The trichome joint, by which the trichome was attached to the leaf tower epidermis, was expanded and filled with essential oil droplets. The undeveloped trichomes assumed a flattened form because of the action of pressing during rolling and shrank during the tea drying process. During the Maofeng tea processing, trichome shedding was caused by disruption of its expanded joint structure and breakdown at the cylindrical wall above the expanded joint.     

中国红茶产销现状与发展前景

回顾了我国和世界其它国家红茶产销情况,分析了我国红茶产销的优劣势,并对我国红茶产业发展前景予以展望,提出了我国红茶产业的发展对策。     

茶籽壳原花青素提取参数优化

应用二次通用旋转组合设计,对茶籽壳提取原花青素的参数进行研究。结果表明:提取时间(X_1),乙醇体积分数(X_2),提取温度(X_3),料液比(X_4)对原花青素的得率均有较显著影响,且呈现X_1>X_3>X_2>X_4。模拟优化后得到提取原花青素参数优化方案为:提取时间28 min,乙醇体积分数60%,提取温度55℃,料液比(g:mL)1:6。     

酸茶营养成分及微量元素分析

按照茶叶等食品的国家标准方法,测定了包括水浸出物、茶多酚、游离氨基酸等在内的7种酸茶常量成分;湿法消化酸茶样品,采用火焰原子吸收分光光度法测定了Fe、Zn、Cr、Cu、Mn和Ni 6种微量元素的含量。结果显示:酸茶中水分、水浸出物、茶多酚、游离氨基酸、可溶性总糖、叶绿素和总黄酮的含量分别为7.16%、49.13%、26.29%、0.88%、19.90%、0.054%和6.56%;酸茶中微量元素的含量Mn﹥Cu﹥Cr﹥Fe﹥Zn,Ni元素未检出。各元素的加标回收率为98.70%～101.80%,相对标准偏差为0.04%～2.35%,准确度和精密度均符合要求。酸茶中茶多酚、可溶性总糖含量较高;火焰原子吸收分光光度法测定酸茶中的金属元素含量是可行的。     

Seasonal Variations in Quality of Kangra Tea ( Camellia sinensis(L) O Kuntze) in Himachal Pradesh

Periodic seasonal variations in infusion quality of orthodox Kangra tea over various growth flushes are reported. Theaflavins, thearubigins and caffeine recorded maximum content during early flush and gradual decline with progress in season, showing a minimum during main flush and slight improvement through backend flush. Flavour profile analysis also revealed qualitative and quantitative seasonal variations in aroma complex. High proportions of provisionally identified flavour components, linalool, geraniol, β-ionone, methyl salicylate, phenyl acetaldehyde, trans -2-hexenal, and several unidentified components with typical Kangra notes recorded during early flush exhibited comparatively lower contents or even total loss through main flush. Flavour quality also registered slight improvement in backend flush over main flush. Results suggest increasing crop productivity during early and backend flushes could enhance profitability.     

Effect of weather conditions on concentration of calcium,manganese, zinc,copper and iron in green tea (Camellia sinensis (L) O kuntze) leaves of North-Western India

Variations of calcium, manganese, zinc, copper and iron contents in green tea leaves due to weather conditions were studied for three cropping seasons with a view to provide information on nutritional requirements to boost productivity. The concentrations of these micronutrients were related to the uptake capability of tea plants as affected by different weather parameters. High temperature and high atmospheric evaporative demand assisted calcium uptake whereas high humidity and high rainfall reduced it. Low temperature and high humidity reduced manganese uptake. High weekly evaporation, weekly relative humidity and accumulated rainfall depressed the uptake of zinc, copper and iron in green tea shoots.     

Effect of green and black teas (Camellia sinensis L.) on the characteristic microflora of yogurt during fermentation and refrigerated storage

The effect of tea on the fermentation and survival of yogurt microorganisms was studied. Green and black teas were added to milk at the beginning of fermentation. Acidity of yogurt products and survival of their microflora were studied during 42 days at 4 °C. Results showed that the presence of tea did not significantly (P < 0.05) influence the yogurt characteristic microorganisms. HPLC studies demonstrated that yogurt bacteria did not affect tea catechins when they were incubated together for 48 h. Indeed, all five products reached about 10⁹ CFU/ml after 6 h of fermentation. Viability during 6 weeks storage at 4 °C varied very little (8.35 < log CFU/ml < 8.65). Similarly, green and black teas had no effect on lactic acid levels of the final products (after 6 weeks of storage, acidity remained above 80 °D). According to these findings, addition of teas or tea catechins to yogurt can be recommended to take advantage of their beneficial properties on human health attributed to their antioxidant and antimicrobial activities.     

加速溶剂提取法快速分析乌龙茶内含呈香组分

加速溶剂提取法（Accelerated solvent extraction,ASE）是近年来最先进的样品前处理技术之一,具有快速高效等特点.本研究应用ASE技术对凤凰单枞乌龙茶（Camellia sinensis）的呈香组分进行富集,设置最优条件是使用40ml乙酸乙酯为提取溶剂,提取压力9MPa,提取温度120℃,可对10.00g乌龙茶样品的香气成分有效提取,提取时间仅为5min;结合气质联用仪分析鉴定.结果表明采用ASE富集凤凰单枞乌龙茶香气组分,从桂花香型凤凰单枞乌龙茶中检测出63种香气组分,其中较高的组分有芳樟醇、橙花叔醇、壬酸、癸酸、香叶醇、十六烷和3,7-二甲基-1,5,7-辛三烯-3-醇.ASE法可对乌龙茶内含香气组分进行无损富集和快速检测,避免茶叶内含不稳定的香气组分被破坏,减少茶叶香气组分检测的误差和不稳定性.     

从油茶饼粕中提取油茶籽多糖和茶皂素的工艺研究

研究从油茶籽饼粕中提取油茶籽多糖和茶皂素的最佳工艺。首先比较水提法、醇提法提取油茶籽多糖和茶皂素的得率和纯度,然后结合大孔吸附树脂层析法对茶皂素的纯化进行进一步研究,确定了油茶籽多糖、茶皂素的最佳提取工艺为:温度75℃,2次浸提,油茶饼粕和水的比例两次分别为1:9和1:5,浸提时间每次各1.5h,油茶籽多糖得率9.09%,质量分数20.67%;茶皂素得率18.19%,其质量分数为62.35%。采用大孔树脂纯化茶皂素,收集体积分数70%醇洗脱溶液,得到90%以上的高纯度茶皂素。     

乳化剂对茶多酚和脂溶性茶多酚抗亚油酸及其乳化体系氧化作用的影响

本文研究了茶多酚和脂溶性茶多酚对亚油酸及其乳化体系抗氧化作用的影响,结果发现茶多酚和脂溶性茶多酚联合处理组在亚油酸及其乳化体系中的抗氧化作用都显著优于茶多酚和脂溶性茶多酚单独处理组。进一步研究茶多酚和脂溶性茶多酚在油/水界面分配系数的实验证明,乳化剂能显著增加水溶性抗氧化剂在油相中的分布,降低脂溶性抗氧化剂在油相中的分布,而增加其在水相中的分布,从而为茶多酚和脂溶性茶多酚联合处理组抗氧化的协同增效作用提供了理论基础。     

Seasonal and clonal variations in some major glycosidic bound volatiles in Kangra tea (Camellia sinensis (L.) O. Kuntze)

Seasonal and clonal variations in glycosidic bound volatile compounds were studied in tea clones representing the three different varieties viz. sinensis, assamica and cambodiensis grown in Kangra region. Glycosidic bound volatile compounds were characterised by GC–MS and quantification of major volatiles was done by GC. (E)-2-hexenal, benzyl alcohol, phenylethanol, linalool, linalool oxides, geraniol and methyl salicylate were the major glycosidic bound volatiles identified in tea shoot. Clonal variations in the quantity were observed in these bound volatiles. Seasonal variations were also observed in the quantity of bound volatiles in regional Kangra clone during three different growth flushes of tea. These variations in glycosidic precursors of volatile compounds were studied in context with orthodox made tea and its quality. These seasonal and clonal variations in precursors of volatile compounds can be directly correlated to the difference in the quality of tea made from these cultivars.     

Effect of cooking on the composition of beans (Phaseolus vulgaris L.) and chickpeas (Cicer arietinum L.)

The effect of cooking on levels of nutrients and anti-nutritional factors in beans and chickpeas was investigated. Significant (p < 0.05) variation existed among the beans and chickpeas with respect to their crude protein, starch, soluble dietary fiber (SDF), insoluble dietary fiber (IDF), total dietary fiber (TDF), resistant starch (RS), trypsin inhibitor activity (TIA), mineral, phytic acid, tannin, sucrose and oligosaccharide (raffinose, stachyose and verbascose) contents. Cooking beans and chickpeas in water significantly increased protein, starch, SDF, IDF, TDF, Mn and P contents (on a dry weight basis), whereas reduced ash, K, Mg, TIA, tannin, sucrose and oligosaccharide contents were observed. Colored beans (black, cranberry, dark red kidney, pinto and small red bean) contained tannins, whereas little tannin in white-colored beans (great northern and white pea bean) and chickpeas (Desi and Kabuli type) was detected.