Extraction of Theanine from Waste Liquid of Tea Polyphenol Production in Aqueous Two-phase Systems with Cationic and Anionic Surfactants

Extraction of theanine from waste liquid of tea polyphenol production was studied in aqueous surfactanttwo-phase system （ASTP） with cationic surfactant （CTAB） and anionic surfactant （SDS）. Results indicate that the region of ASTP is narrow and there is only a two-phase region of cationic surfactant. The increase in concentrations of NaBr and Na2SO4 are beneficial to the formation of ASTP. Theanine concentration in the bottom phase increases with increasing concentration of theanine, whereas the Partition coefficient and extraction rate only change a littlewhen the concentration of theanine is above 0.2 g.L-＇. With the increase of SDS concentration, the phase ratio and the partition coefficient decrease, while the extraction efficiency of theanine increases and the concentration of theanine changes a little in the range from 2.4/7.5 to 2.8/7.2 for SDS/CTAB ratio. The temperature has a notable ef- fect on the concentration of theanine in the bottom phase, partition coefficient and extraction rate of theanine. The increase of waste liquid decreases the phase ratio, increases the concentration and extraction rate of theanine in the bottom ohase, since the orotein and the saccharide enter the bottom nhase with theanine.

Effect of Sunlight Exposure and Different Withering Durations on Theanine Levels in Tea (<i>Camellia sinensis</i>)

Theanine is a non-protein amino acid representing as much as 50% of the total amino acids in black tea and 1% - 2% of dry weight in green tea. It has been shown to be able to reduce high blood pressure, promote relaxation, and inhibit caffeine’s side effects among others. This current study explored the effects of sunlight and withering durations on theanine levels in tea shoots. Theanine content from three leaves and a bud, two leaves and a bud and internodes were detected and quantified by using High Performance Liquid chromatography (HPLC). Sunlight exposure experiment was started at dawn (0600 HRS, GMT + 3.00) when the light intensity was low and tea was collected at three-hour interval throughout the day to (1800 Hrs, GMT + 3.00) when the light intensity had dropped. At the start of the experiment, the theanine levels were significantly high but as the intensity of sunlight increased during the day there was a significant drop in theanine levels, and as the sun set the theanine levels increased significantly again in all samples. The results also showed that theanine levels were significantly increased after 15 hours of withering. Three leaves and a bud withered for 3 hours had mean theanine levels of 1.41% and those withered for 15 hours had mean theanine levels of 3.11%. Internodes exhibited higher mean theanine levels than those of leaves. In the light of these results, it’s evident that withering for a longer period of time and harvesting of tea when the light intensity is low ensure high amount of theanine in tea.

Effect of Seasons on Theanine Levels in Different Kenyan Commercially Released Tea Cultivars and Its Variation in Different Parts of the Tea Shoot

A study was conducted to determine the effect of seasons in 23 different Kenyan commercially released tea cultivars. This was done for three seasons viz: cold and wet, cold and humid, hot and dry. The cold and wet season was shown to be the best for obtaining high levels of theanine while the hot and dry season resulted in decrease in theanine levels in most of the test cultivars thus showing seasonal variation on the levels of theanine. Theanine content was determined using High Performance Liquid Chromatography (HPLC). On average, TRFK 31/8 contained 1.20% dw of theanine and highest in green tea while TRFK 56/89 contained 0.97% dw of theanine and highest in black tea. Green tea contained higher theanine levels than black tea and this has been shown in most of the test cultivars. To achieve the health benefits of theanine, one should drink 4 cups of tea brewed from cultivars with 0.63% dw and more of theanine. Also theanine levels were determined in the different partitions of the tea shoot (4 leaves + bud) and the internode contained the highest theanine levels up to 3.26% dw for both cultivars compared to the leafy partitions.

A Comparative Analysis of Caffeine Extraction Efficiency from Different Tea Varieties and Its Effect on Human Physiology: A Spectrophotometric Investigation

The current work imitates the trivial method which intricates the abstraction along with classification of caffeine accessible in variability of decoction shrubberies which are expended in two different states of India (Telengana & Uttar Pradesh). As per observation individuals of both the states are identical tender of consumption of tea. Abstraction progression tangled variability of stages which are discoursed in the work. In addition, the outcome of drinking of caffeine or the permitted ingestion of caffeine over tea has also been conferred through the work and linked the data with the literature data. In this study, we used a UV-visible spectrophotometer as well as liquid-liquid extraction method to determine the caffeine content in various tea samples. The significance of this study lies in the fact that accurate determination of caffeine content is essential for quality control and labeling of tea products. The UV-visible spectrophotometer method was found to be simple, reliable, and sensitive for the detection of caffeine in tea samples.

茶功能成分的提取方法及其抗运动性疲劳研究进展

茶功能成分主要包括茶多酚、茶氨酸、茶生物碱、茶多糖等,属于抗运动性疲劳的食源性物质。对茶功能成分的提取方法及其抗运动性疲劳作用机制进行阐述,综述了利用水提、有机溶剂提取、微波提取、超声波提取、离子交换、超临界流体提取等方法提取茶功能成分的研究成果,以及茶功能成分对调解机体代谢、清除自由基、增强抗氧化作用、增强骨骼肌抗运动性疲劳作用的研究进展,为开发以茶为原材料的抗运动性疲劳食源性衍生品提供依据。

茶叶酵素无机陶瓷膜过滤工艺优化

为了提高茶叶酵素的澄清度,同时保证茶叶酵素在澄清过程中功能成分得到最大的保留,本试验以夏秋茶发酵所得茶叶酵素为原料,采用单因素实验和响应面试验考察无机陶瓷膜孔径、过膜功率、过膜压力、过膜温度对过膜后酵素液功能成分含量、膜通量、透光率、可溶性固形物含量的影响,旨在优选出最佳的茶叶酵素陶瓷膜过滤条件。结果表明,茶叶酵素陶瓷膜过滤的最佳条件为:膜孔径400 nm、过膜功率47 Hz、过膜压力0.28±0.02 MPa,过膜温度15±2℃,在此条件下,茶叶酵素中茶多酚含量保留率为95.28%,茶氨酸含量保留率为82.91%,锌含量保留率为90.48%,硒含量保留率为91.67%,可溶性固形物含量保留率为84.46%,透光率为85.10%±0.12%,透光率与过膜前相比提高了2.5倍,膜通量为123.25±2.68 m^(3)/(m^(2)·h),该条件既能最大程度的保留茶叶酵素中功能成分的含量,又能使茶叶酵素透亮、均一。因此,采用该条件对茶叶酵素进行过滤澄清方法可行。

不同工艺槐米茶中芦丁冲泡溶出率比较的研究

本研究采用紫外分光光度法对12款槐米茶冲泡液中的芦丁含量进行了测定,研究了不同制作工艺对槐米茶的芦丁冲泡溶出率的影响。结果表明:12款槐米茶经过5次冲泡后,芦丁总溶出率在4.06%~13.13%。不同制作工艺对槐米茶中芦丁的冲泡溶出率有较大影响,芦丁整体溶出率由高到低分别是:熏蒸杀青10 min、晒干、微波炉低火模式处理10 min;熏蒸杀青10 min、晒干、炒黄;挤压破坏槐米结构,大火炒制杀青4 min,继而炒干、炒黄;90℃直接烘干。

紫外可见分光光度法测定肉苁蓉配方茶中总黄酮、总多酚、总多糖及总皂苷的含量

目的:对肉苁蓉配方茶中总黄酮、总多酚、总多糖、总皂苷含量进行检测,为配方茶的质量控制及抗疲劳物质的基础研究提供实验依据。方法:用紫外可见分光光度法测定肉苁蓉配方茶中总黄酮、总多酚、总多糖、总皂苷的含量。结果:肉苁蓉配方茶中总黄酮、总多酚、总多糖及总皂苷的含量分别为8.23%~8.75%、9.30%~9.67%、1.20%~1.58%、1.87%~2.86%。结论:肉苁蓉配方茶中主要成分为黄酮类及多酚类,皂苷及多糖含量较少。

茶叶中茶氨酸的国标检测方法改进研究

基于国家标准GB/T 23193-2017《茶叶中茶氨酸的测定高效液相色谱法》的测定方法,研究建立了快速准确地测定茶叶中茶氨酸含量的高效液相色谱检测方法,茶叶样品通过超声提取15 min(超声功率为500 W)和离心15 min(5000 r/min),能快速完成样品制备。采用Spursil C18高效液相色谱柱(粒径5μm,250 mm x 4.6 mm),流速为1.0 mL/min,柱温为35℃,进样量为20μL,检测波长为210 nm,以纯水为流动相,等度洗脱,茶氨酸在0.00~0.40 mg/mL范围内线性良好,在0.14~0.21 mg/mL的加标范围内,平均回收率为99.1%~100.5%,重复性试验的相对标准偏差(RSD)为2.90%,精密度试验的RSD为1.82%,稳定性实验的RSD为1.53%,样品提取液在20 h内稳定。该改进方法简便、快速,精密度好、准确度高,重复性和稳定性良好,可用于对茶叶中茶氨酸含量的快速测定。

茶叶中铁含量分析技术的比对研究

选择邻菲啰啉分光光度法和石墨炉型原子吸收光谱法测定明前绿茶、大红袍茶和普洱茶3种常见市售茶叶中铁含量。研究发现,在优化的试验条件下,分光光度法和石墨炉型原子吸收光谱法,分别在0~2.0000μg/mL和0~5.0000μg/mL质量浓度范围内,铁的质量浓度与吸光度有良好线性关系。分光光度法和石墨炉型原子吸收光谱法的回收率分别为97.3%~103.8%和97.6%~102.9%,相对标准偏差RSD均小于5%。

Tea Identification through Surface-Assisted Laser Desorption/Ionization Mass Spectrometry

We have applied surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) usingtitanium dioxide nanoparticles(TiO2NPs)as the matrix and captopril (CAP) as internal standard for the determination of the concentrations of theanine and four catechins—catechin, (_)-epigallocatechin (EGC), (_)-epicatechin gallate (ECG), and (_)-epigallocatechin gallate (EGCG).Under the optimal conditions (240 nM TiO2 NPs and 10 μM CAP), this SALDI-MS approach provides linearity of 0.3– 80 (r= 0.990), 1.2–100 (r= 0.987), 4–120 (r= 0.995), 6–120 (r= 0.983), and 2–120 μM (r= 0.991) for theanine, catechin, EGC, ECG, and EGCG, respectively. The limits of detection (LODs;S/N = 3)for theanine, catechin, EGC, ECG, and EGCG provided by this SALDI-MS approach are 0.1, 0.35, 1.0, 1.45, and 0.5 μM, respectively. This approach provides spot-to-spot and batch-to-batch variations of less than 10% and 13%, respectively, for the analysis of tea samples.With advantages of simplicity, accuracy, precision, and great reproducibility, we have applied the SALDI-MS approach for the analysis of tea samples, with identified peaks for theanine, catechin, EGC, ECG, and EGCG. Tea samples from Taiwan and four other areas have various SALDI-MS profiles, showing their potential for differentiation of tea samples from different sources. Our result also shows that tea samples harvested in different seasons and counties in Taiwan provide significantly different MS profiles. The amounts of theanine and EGC in the Oolong tea from Lishan are much higher than those in the other tea samples.

Selected Inorganic Nutrients in Black Tea from Three Tea Growing Agro-Ecological Areas in Kenya

The tea plant absorbs dissolved nutrients from soils for its normal growth and development, though to different extents. Nutrients play vital roles in various metabolic processes, their deficiency or excess being deleterious to living organisms. A study was carried out to quantitatively assess the inorganic nutrient content (K, P, Ca, Mn, Fe, Zn and Cu) of twelve black tea samples sourced from Murang’a, Meru and Kisii tea growing agro-ecological areas in Kenya. K and P were quantified using a flame photometer and a UV-Vis spectrophotometer respectively whereas Ca, Mn, Fe, Zn and Cu were quantified using an Atomic Absorption Spectrophotometer (AAS). The general accumulation pattern of the inorganic nutrients in the tea samples was established to be;K (1.6% ± 0.05%-2.1% ± 0.01%) > P (0.30% ± 0.01%-0.37% ± 0.04%) > Ca (0.16% ± 0.01%-0.62% ± 0.03%) > Mn (0.07% ± 0.009%-0.13% ± 0.004%) > Fe (136 ± 8-320 ± 5 μg/g) > Zn (27 ± 1-39 ± 7 μg/g) > Cu (10 ± 3-16 ± 1 μg/g). Statistically significant differences (p < 0.05) were observed in the inorganic nutrient contents of the black tea from the different tea factories as well as agro-ecological areas. These data demonstrate the tea plant’s ability to accumulate the studied nutrients, further underlining tea consumption as a potential dietary source of the nutritionally essential inorganic nutrients.

72份武汉茶叶氨基酸检测与高茶氨酸品种筛选

本文对来自湖北的72份茶叶原样进行检测分析,拟选育出高茶氨酸品系。实验参考《植物中游离氨基酸的测定》(GB/T 30987—2020)中的方法,结合高效液相色谱仪对茶叶中各种游离氨基酸的含量进行检测分析,对其中茶氨酸含量与游离氨基酸含量进行综合分析评估,并筛选出优质高茶氨酸品种作为推广种植质资源。实验通过对茶氨酸总含量、茶氨酸在游离氨基酸中的占比,以及茶叶品种差异进行分析,为高茶氨酸茶的实现提供可参考思路。本文为选育高茶氨酸品系提供一种方案,旨在加强高茶氨酸品种的开发,提升茶叶产品质量和丰富度,便于茶叶产品推广,增强中国茶叶的影响力、竞争力。

Quantitative Estimation of γ-Glutamylethylamide in Commercially Available Made Teas [Camellia sinensis (L.) O. Kuntze, Theaceae] in Kenya

A study was carried out to quantitatively estimate the L-theanine content in 19 teas commercially available in the Kenyan market by High Performance Liquid Chromatography (HPLC). The test tea samples analyzed were green (n = 4), black (n = 8) and flavored (n = 7) teas from different origins viz., Kenya (n = 4), Uganda (n = 2), Tanzania (n = 5), Rwanda (n = 4), Cameroon (n = 1) and Sri-Lanka (n = 2) commercially available in the Kenyan market. The estimated Limit of Detection (LOD) of the current method was 0.01% L-theanine. The L-theanine content ranged from below the detection limit (<0.01% L-theanine) to 1.60% L-theanine on a dry weight (d.w) basis. Statistically significant differences (p < 0.05) were observed in the L-theanine contents of black, green and flavoured teas. Rwandan green tea contained the highest L-theanine content with 1.60% d.w. whereas six of the seven flavoured teas had very low theanine levels (<0.01%) that could not be quantified by the current method.

氧化应激及天然抗氧化剂对阿尔茨海默病的缓解作用

衰老是阿尔茨海默病(Alzheimer’s disease,AD)等神经退行性疾病的主要危险因素。氧化应激和自由基具有重要的生物学功能,氧化还原失衡导致氧化应激,与包括AD在内的许多人类疾病的病理生理有关。本文综述了活性氧(ROS)参与神经退行性疾病发病的相关机制,特别是氧化应激与AD其他关键机制的相互作用,并总结了茶多酚、L-茶氨酸、虾青素、EGb761、大豆异黄酮和烟碱在细胞和动物模型中对AD的防护作用以及在临床上对相关疾病的缓解作用。希望该综述能为AD的预防和治疗策略提供一些见解。

Effect of Drinking Green Tea on Mental State of Humans

Tea is one of the most widely consumed beverages in the world,among which green tea is most common in China and Korea.Green tea constituents possess a great value to human health wherein lots of clinical studies and investigations were conducted by researchers and experts.However,there are still increasing demands and interest on the health properties of green tea,especially its effects on mental state of human brains.Based on the collated clinical studies,green tea was used to improve mental alertness and thinking.Thus,higher consumption of green tea was associated with a lower prevalence of cognitive impairment.This review summarizes the effects of drinking green tea on the mental state of human brains.Green tea contains a unique set of L-theanine and epigallocatechin gallate(EGCG) that possess biological activities in antioxidant,anti-memory loss,and antiproliferative assays potentially relevant to the prevention and treatment of various forms of brain damage.Theanine in green tea may play a role in reducing stress.The use of highly innovative method of reading and mental behavior of the human brain's response with the intake of green tea thru neuroimaging was also covered in this review.

不同茶树品种“梁野炒绿”理化品质分析

【目的】探明不同品种制作的武平绿茶——“梁野炒绿”的理化成分差异,为筛选适制梁野炒绿的品种及后续产品品质提升提供理论基础。【方法】本研究对‘福云6号’‘梅占’‘乌牛早’‘龙井43’这4个品种制作的“梁野炒绿”进行了感官与生化成分鉴定。【结果】感官审评发现,乌牛早品种炒绿内质综合得分最高,极显著高于其他3个品种(P<0.01),其次是梅占品种和龙井43;生化成分鉴定表明:水浸出物含量在梅占品种绿茶中均显著高于其他品种(P<0.05),茶多酚含量在梅占和乌牛早绿茶中均显著高于其他两个品种(P<0.05);乌牛早品种炒绿游离氨基酸总量最高,酯型与非酯型儿茶素比值(1.44)、儿茶素苦涩味指数(5.68)、酚氨比(3.88)均比其他品种低;氨基酸组分分析表明,茶氨酸含量(8.971~14.942 mg·g^(-1))在福云6号中极显著高于其他品种,天冬氨酸含量(1.854~2.506 mg·g^(-1))在乌牛早中极显著高于其他品种(P<0.01),谷氨酸含量(1.690~2.244 mg·g^(-1))在梅占和乌牛早炒青绿茶中显著高于其他2个品种(P<0.05);相关性分析表明,茶叶感官审评得分与水浸出物含量呈正相关(R=0.65,P<0.05),与酚氨比、酯型与非酯型儿茶素比值(P<0.05)、儿茶素苦涩味指数呈负相关。【结论】4个品种中乌牛早最适宜制作“梁野炒绿”。

茶白星病侵染对茶树特征性生化成分的影响及相关性分析

为明确茶白星病侵染对茶树特征性生化成分的影响及病害程度与茶树生化成分的相关性,采用紫外分光光度法和高效液相色谱法测定健康鲜叶和茶白星病不同危害程度叶片中的茶多酚、游离氨基酸、没食子酸、可可碱、咖啡碱、茶氨酸、EGC、C、EC、EGCG、GCG和ECG含量,分析茶白星病侵染对茶树特征性生化成分的影响,并结合相关性分析和通径分析探讨茶树特征性生化成分与茶白星病危害严重度的关系。结果表明,茶白星病侵染后茶树叶片中游离氨基酸、茶氨酸含量升高,增加幅度分别在12%~54%和42%~83%之间,咖啡碱含量降低,降幅在10%左右。从健康鲜叶到重度受害鲜叶,可可碱、没食子酸、茶多酚、儿茶素总量、酯型儿茶素、EGCG、ECG和GCG含量变化一致,均呈现先下降后上升再下降趋势,中度受害叶片中含量最高;非酯型儿茶素、EGC和EC含量变化则截然相反,呈现先升高后下降再升高的趋势,中度受害叶片中含量最低。相关性分析显示,没食子酸和C含量与茶白星病病情指数呈显著和极显著正相关(相关系数分别为0.680和0.831),游离氨基酸和茶氨酸含量与茶白星病病情指数呈极显著负相关(相关系数分别为-0.990和-0.913)。通径分析结果表明茶氨酸和没食子酸是影响茶白星病危害严重度的主要决定性生化因子。

粤北油茶粕中茶皂素热水提取工艺优化

以粤北脱脂油茶粕为试验研究的原材料,利用热水提取茶皂素。以茶皂素的提取率为主要考查指标,利用可见分光光度计测定茶皂素含量。通过单因素试验和正交试验探究浸提温度、浸提时间、料液比和浸提次数对茶皂素含量的影响。结果表明,茶皂素热水提取的最优工艺条件为浸提温度65℃,浸提时间2 h,料液比1∶10(g∶mL),浸提次数2次,在此条件下,茶皂素提取率为6.86%。

气相色谱/串联三重四级杆质谱法测定绿茶中L-茶氨酸、咖啡因、茶多酚和十六烷酸的含量

建立了绿茶中L-茶氨酸、咖啡因、茶多酚和十六烷酸的气相色谱-串联三重四级杆质谱(gas chromatography-tabdem triple quadrupole mass spectrometry,GC-MS/MS)同时测定分析方法。茶叶样品经85℃热水浸泡后,用乙腈提取,采用QuEchERs法净化,HP-5MS色谱柱分离,三重四级杆质谱多反应监测(multiple reaction monitoring,MRM)模式有效降低茶叶基质的背景干扰,GC-MS/MS分析检测。该检测方法的检出限为0.001~0.003 mg/kg,方法验证试验结果表明,该类化合物的平均回收率为73%~104%,相对标准偏差为3.0%~10.5%。通过对市售茶叶样品的检测,进一步验证该方法重现性好,准确度高,操作简单,适用于绿茶中L-茶氨酸、咖啡因、茶多酚和十六烷酸的检测。