共查询到18条相似文献,搜索用时 93 毫秒
1.
2.
L-茶氨酸是茶树体内特征性非蛋白氨基酸,是影响茶叶品质的重要指标之一。L-茶氨酸具有抗疾病、保护神经和镇定安神等保健功效。大部分白化茶树拥有高含量的游离氨基酸和L-茶氨酸,引领着茶树资源的选育方向,因此研究白化茶树L-茶氨酸的高累积机理至关重要。该文主要对白化茶树L-茶氨酸的差异累积、L-茶氨酸在茶树体内的含量及分布、合成代谢途径以及影响因素等方面进行文献综述。旨在为白化茶树种质资源的选育及其L-茶氨酸的高累积机理研究提供参考,并对L-茶氨酸在保健领域的研究方向进行展望。 相似文献
3.
4.
5.
6.
中国人饮茶的历史已有上千年之久,L-茶氨酸(L-Theanine)作为茶叶中特有的游离氨基酸,使人们在饮茶时享受到一种放松、旷怡身心的感觉。此外,茶氨酸还具有抗抑郁、降血压、提高学习能力、抗疲劳、免疫等作用。L-茶氨酸是一种安全、无毒、集多种生理功能于一身的功能因子,且不会产生任何副作用,能在维持和增进国民健康上做出一定的贡献,因此它在国外市场上已深受消费者的欢迎。工业上生产茶氨酸的方法主要有茶愈伤组织培养法、茶叶提取法、化学合成法以及微生物酶法等。关于茶氨酸的功能和合成的报道已屡见不鲜,本文主要介绍了国内外主要生产茶氨酸的厂家和世界茶氨酸工业化生产和应用的发展动向,以及茶氨酸的安全性及其在国内外相关允许添加的法规情况。 相似文献
7.
《食品与发酵工业》2019,(22):6-11
L-茶氨酸是茶叶中一种独特的非蛋白质氨基酸。γ-谷氨基甲酰胺合成酶可以催化L-谷氨酸、乙胺和ATP合成L-茶氨酸,但反应成本较高。为了提高L-茶氨酸的生产效率,该研究开发了直接发酵生产L-茶氨酸的新方法。首先,在大肠杆菌基因组上双拷贝Methylovorus mays来源的γ-谷氨酰甲胺合成酶基因gmas,获得了一株遗传稳定的用于L-茶氨酸生产的重组菌株。其次,在5 L罐中采用流加乙胺的方式发酵20 h,L-茶氨酸产量达到30. 45 g/L,糖酸转化率达到20.17%。最后,根据L-茶氨酸的物化性质拟定出合适的分离提取路线,从发酵液中获得了98.51%纯度的L-茶氨酸成品,总提取收率可达到70.34%。该方法操作简单,原料成本较低,具有较好的工业应用前景。 相似文献
8.
茶氨酸是茶叶特有一种氨基酸,50年代首次从茶叶中提取、精制出茶氨酸,此后许多学者对其进行大量研究工作,包括体内吸收与代谢,生理功能及在食品中应用,该文对茶氨酸国内外最新研究进展进行综述。 相似文献
9.
《食品安全导刊》2017,(24)
本文研究了柱前衍生测定茶叶中L-茶氨酸含量的方法。茶叶中的L-茶氨酸用热水提取后,经2,4-二硝基氟苯衍生后上高效液相色谱法测定。色谱条件为:色谱柱(Kromasil C18柱4.6 mm×250 mm,5μm);流动相:乙腈︰磷酸盐溶液(pH=6.5)=15︰85梯度洗脱;检测波长:360 nm;流速:1.0 mL/min;柱温:35℃;进样:5μL。本方法检出限4 mg/kg,在1.0~50.0μg/mL呈现良好的线性关系(r=0.999 9),衍生后的样品室温25℃放置6天内稳定,重现性试验相对标准偏差0.16%(n=6),回收率为96.4%~102.2%。本高效液相色谱法可以准确地测定茶叶中L-茶氨酸的含量。 相似文献
10.
不同茶叶中茶氨酸含量的测定比较 总被引:2,自引:0,他引:2
建立用高效液相色谱法测定茶叶中茶氨酸的方法,用于比较红茶、绿茶、甜茶等各种茶叶中茶氨酸的含量.采用的色谱柱为C18色谱柱,以甲醇和0.05%体积分数的三氟乙酸溶液为流动相进行梯度洗脱.流速为0.8ml/min,紫外检测波长为208nm,柱温30℃,外标法定量.结果表明,在一定浓度的茶氨酸浓度范围内,峰面积与质量浓度具有良好的线性关系,以茶氨酸浓度为横坐标,建立线性回归方程Y=4299.366X 14.828,相关系数R为0.9997.通过对各种茶叶的测定,比较其中含有的茶氨酸的量.茶氨酸的加样回收率为101.06%,对各种茶叶方法精密度相对标准偏差均小于为0.5%,该操作方法简便、快速、准确.测定发现红茶、绿茶、甜茶等各种类型的茶叶中茶氨酸的含量与茶叶类别有关. 相似文献
11.
After consumption of tea, L-theanine enters systemic circulation and is assumed to enter the brain. Several human studies indicate that L-theanine influences brain functioning. Knowledge about the pharmacokinetics of L-theanine facilitates further study of this health effect. Volunteers received 25–100 mg of L-theanine as tea, as L-theanine-enriched tea, and as biosynthetic L-theanine in aqueous solutions. Plasma was analysed for L-theanine content after which data were fitted with a 1- compartment model. For all interventions, the lag time was approximately 10 min and half-lives of absorption and elimination were approximately 15 and 65 min respectively. After approximately 50 min, maximum plasma concentrations of between 1.0 and 4.4 mg/L were achieved. Maximum plasma concentration and area under the plasma-concentration–time curve were dose-proportional. This knowledge allows prediction of plasma concentrations for various dose regimens supporting further study of a health benefit of L-theanine. 相似文献
12.
Guilan Li Jingjing Kang Xiangyang Yao Yinqiang Xin Qi Wang Yin Ye Lan Luo Zhimin Yin 《European Food Research and Technology》2011,233(3):427-435
L-theanine is a natural amino acid in green tea and it has been well known for its activities of relieving depression and
neuroprotection. However, cytoprotective effect and its mechanism of L-theanine on hepatocytes have not been reported. The
objective of this work was to investigate the hepatoprotective effect of L-theanine as well as its mechanism by using the
human hepatic L02 cells injured by hydrogen peroxide (H2O2). Results showed that L-theanine dose dependently decreased H2O2-induced cell viability loss and lactate dehydrogenase (LDH) release. L-theanine pretreatment improved nuclear morphology
of the cells injured by H2O2. By using flow cytometric analysis, we found that L-theanine significantly inhibited H2O2-induced cell apoptosis. Further, L-theanine attenuated H2O2-induced reduction in pro-caspase3 and cleavage of poly (adenosine diphosphate-ribose) polymerase (PARP). H2O2-activated p38 mitogen-activated protein kinase (MAPK) was also inhibited by L-theanine. These data suggest that L-theanine
could protect L02 cells against H2O2-induced apoptosis via suppression of p38 MAPK. L-theanine might potentially be useful in the prevention and treatment of
liver diseases. 相似文献
13.
以6-羟基多巴胺(6-hydroxydopamine,6-OHDA)诱导的SH-SY5Y细胞系作为帕金森病(Parkinson’sdisease,PD)体外细胞模型,探究茶提取物(L-茶氨酸、咖啡碱、茶多酚、表没食子儿茶素没食子酸酯(epigallocatechin-3-gallate,EGCG)、茶黄素、茶色素)和两种纳米EGCG对SH-SY5Y细胞的毒性和对6-OHDA诱导的SH-SY5Y细胞保护作用的差异,综合评价茶提取物治疗PD的潜力。结果表明:茶提取物毒性作用由弱到强为茶多酚<L-茶氨酸<茶色素<咖啡碱<茶黄素<EGCG;保护作用由强到弱为茶黄素>EGCG>茶多酚>茶色素>咖啡碱>L-茶氨酸;茶黄素(0.2 μg/mL)和EGCG(0.9 μg/mL)预处理6-OHDA诱导的SH-SY5Y细胞,细胞存活率分别为(99.59±2.24)%和(95.84±2.50)%,保护作用明显强于其他茶提取物;相较于EGCG,纳米EGCG具有毒性作用更弱和保护作用更强的特点。由此可知,茶作为一种日常饮品,具有较好地治疗PD的潜力。 相似文献
14.
15.
16.
《Trends in Food Science & Technology》1999,10(6-7):199-204
Since ancient times, it has been said that drinking green tea brings relaxation. The substance that is responsible for a sense of relaxation, is theanine. Theanine is a unique amino acid found almost solely in tea plants and the main component responsible for the exotic taste of ‘green’ tea. It was found that L-theanine administered intraperitoneally to rats reached the brain within 30 min without any metabolic change. Theanine also acts as a neurotransmitter in the brain and decreased blood pressure significantly in hypertensive rats. In general, animals always generate very weak electric pulses on the surface of the brain, called brain waves. Brain waves are classified into four types, namely α,β,δ and θ-waves, based on mental conditions. Generation of α-waves is considered to be an index of relaxation. In human volunteers, α-waves were generated on the occipital and parietal regions of the brain surface within 40 min after the oral administration of theanine (50–200 mg), signifying relaxation without causing drowsiness. With the successful industrial production of L-theanine, we are now able to supply Suntheanine™ (trade name of L-theanine) which offers a tremendous opportunity for designing foods and medical foods targeting relaxation and the reduction of stress. Taiyo Kagaku Co., Ltd, Japan won the 1998 ‘Food Ingredient Research Award’ for development of Suntheanine™ at Food Ingredients in Europe (Frankfurt). The judges felt it was a particularly well-documented and fascinating piece of research. 相似文献
17.
可供开发食品添加剂(Ⅷ):L-茶氨酸及其生理功能 总被引:10,自引:0,他引:10
L-茶氨酸是几仅见于绿茶中一种特殊氨基酸,对茶叶的质量至关重要。日本自1964年起批准作为食品添加剂——风味增强剂,我国尚未列入GB2760准用名单。其可作为茶饮料等食品的增味剂;此外尚有松弛神经紧张、保护大脑神经、降血压、抗疲劳等生理作用。 相似文献
18.
在我国悠久的种茶历史中,茶树花由于具有会与茶叶争夺营养的特点,常常作为废弃物处理,导致该资源得不到很好地开发和利用。研究发现,茶树花成分与茶叶基本相似,含有丰富的营养活性物质。随着越来越多的学者意识到茶树花的高价值,有关茶树花营养成分及生理功能的研究逐渐深入开展。茶树花中黄酮类化合物含量高于其他花卉。黄酮类物质具有抗氧化、降血脂、抗菌及抗病毒、抗肿瘤、抗炎等生物活性,可作为制备保健食品或药品的良好原料。目前从茶树花中提取黄酮物质的常用方法有热回流提取法、有机溶剂萃取法、超声和微波辅助萃取法等,分离纯化方法有柱层析色谱法,化学成分检测方法常用色谱质谱联用法。本文在分析黄酮类化合物的基本结构和理化性质的基础上,总结了茶树花黄酮类化合物生理功能,综述了其提取分离、纯化、检测方法的研究进展,旨在为大规模开发和利用茶树花黄酮提供技术储备,为今后深入研究与广泛应用提供参考。 相似文献