橡木桶陈酿对红葡萄酒中黄烷-3-醇和原花色素的影响

本文以华夏酿酒有限公司2004年度赤霞珠为试材,研究了美洲、欧洲和欧美三种类型橡木桶陈酿对黄烷-3-醇和原花色素含量及组成的影响。结果表明,橡木桶陈酿过程中,(-)-表儿茶素((-)-epicatechin,EC)、(-)-表儿茶素没食子酸酯((-)-epicatechingallate,ECG)、(-)-表棓儿茶素没食子酸酯((-)-epgallocatechingallate,EGCG)含量上升,(+)-儿茶素((+)-catechin,CAT)保持相对稳定,而(-)-表棓儿茶素((-)-epigallocatechin,EGC)略有下降。原花色素含量下降,平均聚合度降低。不同类型的橡木桶对两者含量的影响不同。     

微波对茶多酚结构及其儿茶素组成的影响

以茶叶为原料，研究了微波对茶多酚结构及其儿茶素的影响，结果表明，微波短时处理茶叶，茶多酚的化学结构无明显变化，但其主要成分－－儿茶素的组成发生了变化。EGCG（表没食子儿茶素没食子酸酯）和ECG（表儿茶素没食子酸酯）两种组分有所下降，下降率分别达3．5％和3．4％，并出现GCG（没食子儿茶素没食子酸酯），增加量达5．2％，但与用沸水提取0．5h相比，儿茶素组分变化幅度小。     

湖南红茶品质特征分析及其等级判别模型的构建

本研究对26个湖南省特级、一级和二级工夫红茶样品进行感官审评与理化分析,对茶多酚、游离氨基酸等重要品质成分进行单因素方差分析、主成分分析以及判别分析,并构建其等级典型判别函数模型。结果表明:在特级红茶中,关键品质成分茶多酚、游离氨基酸、咖啡碱、茶黄素含量最多,一级红茶次之,二级红茶最少。在不同等级的湖南红茶中,游离氨基酸、茶氨酸、表没食子儿茶素（EGC）含量无显著性差异,而表儿茶素（EC）、表没食子儿茶素没食子酸酯（EGCG）、茶黄素-3-没食子酸酯（TF-3G）、茶黄素-3’-没食子酸酯（TF-3'G）含量具有显著（P<0.05）性差异。建立的典型判别模型对不同等级湖南红茶的分类具有较好的准确性,其自身验证法的准确率达100%,交互验证法的准确率达84.62%。通过对湖南不同等级工夫红茶的品质化学特征的分析及典型判别模型的构建,本研究为湖南红茶的等级划分提供了一种合理的量化方法。     

儿茶素的分析比较研究

本文首先研究了采用不同标样儿茶素(C)，表儿茶素(EC)和没食子儿茶素没食子酸酯(EGCG)对样品茶多酚中总儿茶素含量分光光度法测定带来的影响，其测定结果儿茶素纯度分别为51．98％，49．59％和82．39％，相对标准偏差分别为0．65％，1.79％和2．28％，回收率分别为94．19％，93．46％和102．4％。结果表明使用异构体C和EC作标样测定结果相近，而采用分子量较大的EGCG作标样时结果偏高。最后本文采用高效液相色谱法(HPLC)对样品茶多酚进行了定性定量研究，结果表明C、EC、EGC(表没食子儿茶素)、ECG(表儿茶素没食子酸酯)和EGCG等五种儿茶素单体的含量分别为5．05％、10．38％，、25．96％、1．98％，和10．18％，总儿茶素含量为53．5％，其测定结果与分光光度法(以C为标样）所测结果相一致。     

玉米黄烷酮-3-羟化酶原核表达条件对香橙素生成量的影响

香橙素是类黄酮代谢途径中重要的中间化合物,黄烷酮-3-羟化酶(flavanone-3-hydroxylase,F3H)能以柚皮素为底物催化C3位接羟基从而生成香橙素.为实现香橙素绿色发展,该研究利用微生物法,对来自玉米的Zmf3h构建大肠杆菌原核表达系统后诱导ZmF3H蛋白表达.通过发酵实验验证ZmF3H在胞内可溶性表...     

祁门红茶多酚提取工艺优化及其组成鉴定

以祁门红茶为原料,优化了红茶多酚提取的工艺条件。通过单因素实验考察乙醇体积分数、提取温度、提取时间、料液比、p H对红茶多酚提取率的影响,并进一步采用正交实验优化提取工艺,得到最佳工艺为:乙醇体积分数60%,提取温度70℃,提取时间2.5 h,料液比1∶50(g/m L),p H4。在此工艺下,提取两次后红茶多酚提取率为(214.23±6.29)mg/g。采用UPLC-DAD鉴定祁门红茶的多酚组成,结果表明,祁门红茶多酚的主要成分为没食子酸、没食子儿茶素、表儿茶素、表没食子儿茶素没食子酸酯、表儿茶素没食子酸酯、儿茶素没食子酸酯、茶黄素、茶黄素-3-没食子酸酯、茶黄素-3′-没食子酸酯和茶黄素双没食子酸酯。     

8种单体多酚对葡萄酒微生物的抑菌活性比较

酚类化合物不仅能赋予葡萄酒丰富的色泽、风味和抗氧化活性,还能抑制葡萄酒微生物的生长。为了比较不同多酚化合物抑菌能力的大小,用牛津杯测试法研究了不同质量浓度(2、5、10 g/L)单体多酚(儿茶素、表儿茶素、没食子酸、表没食子儿茶素没食子酸酯(epigallocatechin-3-gallate,EGCG)、鞣花酸、杨梅酮、槲皮素和山奈酚)对引起葡萄酒病害的代表菌种:乳酸菌、醋酸菌和酵母菌的抑制作用。结果表明:在8种供试多酚中,杨梅酮、槲皮素和EGCG抑菌能力相对较强;黄烷-3-醇类化合物对醋酸菌和酵母菌的抑制能力比乳酸菌更强,没食子酸则恰好相反;山奈酚对所有供试菌株都没有抑菌能力。多酚能在一定程度上抑制葡萄酒微生物的生长繁殖。     

陈年生普与熟普的黄烷醇类活性成分分析

采用Folin-Ciocalteu比色法和LC-DAD-ESI-MS法对陈年生普(以下简称APT)和熟普(以下简称YPT)中总多酚(The total phenolic,TPC)和黄烷醇类活性成分进行分析。研究结果表明,从APT和YPT中确定了8种黄烷醇类活性成分,它们分别是儿茶素(C)、表儿茶素(EC)、表儿茶素没食子酸酯(ECG)、表没食子儿茶素(EGC)、表没食子儿茶素没食子酸酯(EGCG)、没食子儿茶素(GC)、没食子儿茶素没食子酸酯(GCG)、儿茶素没食子酸酯(CG)。2种茶中GC含量差异不显著,APT中的TPC和其余7种黄烷醇类化合物含量均显著高于YPT中。不同产地普洱茶的TPC和8种黄烷醇类化合物含量差异不显著,不同年份差异显著。主成分分析法(PCA)和层次聚类分析(HCA)依据TPC和黄烷醇类化合物能将APT和YPT很好的聚类,成功区分出APT和YPT样品;除GC外的其余7种黄烷醇类化合物和TPC均是很好的化学标记。     

不同架式下‘桂葡6号’葡萄果皮中黄烷-3-醇组分分析

以不同发育期的‘桂葡6号’葡萄果实为试验材料,应用高效液相色谱(HPLC)分析不同架式下‘桂葡6号’葡萄果皮中黄烷-3-醇组分特征。结果表明,在整个果实发育期,3种架式下的‘桂葡6号’葡萄黄烷-3-醇组分中表棓儿茶素含量最高,表儿茶素和表儿茶素没食子酸酯次之,儿茶素含量最低。3种架式下的‘桂葡6号’葡萄黄烷-3-醇总量及组分存在显著性差异。单臂篱架处理果皮中表儿茶素含量在采收期显著高于30°"V"形篱架和60°"V"形篱架处理,但表儿茶素没食子酸酯的含量和比例在采收期均显著低于其他两个"V"形架处理,30°"V"形架处理葡萄果皮中黄烷-3-醇总量和三羟基化黄烷醇的比例最高。从提升葡萄酒柔顺度和改善口感的角度考虑,生产上建议‘桂葡6号’选择30°"V"形篱架的整形方式。     

高效液相色谱法测定茶多酚中EGCG和和EGG的含量

目的:建立茶多酚中表没食子儿茶素没食子酸酯(EGCG)和表儿茶素没食子酸酯(ECG)的高效液相色谱含量测定方法.方法:以Diamonsil C18(4.6mm ×200mm,5μm)为色谱柱,流动相为甲醇-0.1%磷酸水溶液(68:32),流速为1.0mL·min-1,检测波长为279nm,柱温25℃,进样量为20μL.结果:EGCG的进样量在0.1～6μg范围内,ECG的进样量在0.05～1.2μg范围内与峰面积呈良好的线性关系.平均加样回收率分别为EGCG:97.57%、ECG:96.60%,RSD分别为EGCG:1.93%、ECG:1.53%.结论:本方法简便,准确,重复性好,可作为荼多酚中EGCG和ECG的含量测定方法.     

The modulation of endothelial cell gene expression by green tea polyphenol-EGCG

Human and animal studies have shown that green tea consumption is associated with a reduced risk of some cancers. This has been attributed to its polyphenol components, in particular (-)-epigallocatechin gallate (EGCG). In addition to be a cancer chemopreventive agent, EGCG inhibits angiogenesis, thus reducing tumor growth and metastasis. We tested EGCG modulation on the gene expression profile of endothelial cells stimulated by VEGF using Affymetrix microarrays. A total of 421 genes were up-regulated and 72 genes were down-regulated at the false discovery rate of 5% by VEGF, EGCG, and EGCG pretreatment followed by VEGF stimulation. The changes in the expression of several pivotal genes were validated by real-time PCR. Furthermore, we have identified two signaling pathways (Wnt and Id) involved in cell proliferation were inhibited by EGCG treatment, suggesting the negative regulation of EGCG on cell proliferation. Our results also indicate that the antiangiogenesis effect of EGCG is partially mediated through its broad inhibition on endothelial cell proliferation. Our data further support earlier observations that the anticancer effect of EGCG is mediated through changes in the expression of genes that are associated with cell proliferation.     

A Comparative Study of Phenolic Antioxidant Activity and Flavonoid Biosynthesis‐Related Gene Expression Between Summer and Winter Strawberry Cultivars

Strawberry (Fragaria ananassa Duch.) possesses good antioxidant properties. Phenolic compounds in strawberries, such as anthocyanins and ellagic acid, mainly act as antioxidants. This study aimed to compare the phenolic content and expression patterns of genes involved in flavonoid biosynthesis between summer and winter strawberry cultivars affected by seasonal variation, degree of ripeness, and genotype. Antioxidant activity and the total content of phenols and flavonoids decreased with fruit ripening. Most notably, summer strawberry cultivars showed higher antioxidant activity than winter cultivars. The expression patterns of flavonoid biosynthetic genes tested were cultivar‐dependent and were also affected by ripening. These results help us understand the nutritional and physiological characteristics of selected cultivars and provide a range of information for strawberry consumption.     

不同采摘时期贵定鸟王茶鲜叶次生代谢产物差异分析

目的分析不同采摘时期贵定鸟王茶的次生代谢产物差异。方法基于代谢组学技术对不同采摘时期贵定鸟王茶的次生代谢产物进行测定,利用XCMS软件和METLIN数据库对代谢物进行定性分析,用SIMCA-P软件进行定量分析和差异化合物筛选。结果茶树样本间分离趋势明显,且春茶和秋茶代谢物差异最大。不同采摘时期鸟王茶之间共筛选出12种关键差异化合物,包括3种儿茶素、3种黄酮醇类、2种糖类、2种茶黄素类、1种氨基酸和1种黄酮糖苷。通路富集分析显示这些差异化合物主要分布于类黄酮生物合成代谢途径中。此外,儿茶素、糖类和氨基酸类物质在春茶中含量最高,黄酮醇、茶黄素和黄酮糖苷类物质在夏茶中含量最高,秋茶中差异化合物的含量最低。结论贵定鸟王春茶更适合加工成绿茶,而夏茶更适合加工成红茶。     

Diversity among various forms of catechins and its synthesizing enzyme (phenylalanine ammonia lyase) in relation to quality of black tea (Camellia spp.)

BACKGROUND: Quality of tea depends on the cultivar and climatic conditions. Biochemical pathways within the plant and climatic factors can result in noticeable changes in chemical composition, which determine the quality of tea. Black tea quality attributes are influenced by various forms of catechins, namely gallated, non‐gallated, dihydroxylated and trihydroxylated catechins and their ratios. Hence the variations in grouped catechins and their synthesizing enzyme in relation to quality of south Indian black tea grown in different seasons and different cultivars were studied. RESULTS: Gallated, non‐gallated, dihydroxylated, trihydroxylated catechins and catechin index were significantly higher in crop shoots harvested during summer. A significant and wide diversity in various forms of catechins was noticed among the cultivars tested. Among the cultivars, UPASI‐3 registered the higher amount of various forms of catechins and activity of phenylalanine ammonia lyase (PAL), followed by UPASI‐9 and UPASI‐17 respectively, while the lowest amount was exhibited by ‘Assam’ seedlings and TRI‐2043. CONCLUSION: Overall quality as evaluated by tea tasters was positively correlated to the cultivars and seasons tested. This positive correlation can be attributed to higher levels of grouped catechins and PAL activity. Thus the contents of various forms of catechins could be the most important quality parameter of the south Indian black teas. Copyright © 2010 Society of Chemical Industry     

Comparative analysis of flavonoids in white and red table grape cultivars during ripening by widely targeted metabolome and transcript levels

The flavonoid metabolites were compared between red ‘Summer Black’ (SB) and white ‘Shine Muscat’ (SM) table grapes during fruit development based on widely targeted metabolome. A total of 134 flavonoids were identified in two cultivars, including 37 flavones, 33 flavonols, and 11 anthocyanidins, and so on. From young to veraison, the composition and the content of most flavonoids were decreasing in both cultivars but increased at maturation in SB. In general, SB has higher flavonoid compositions and content than SM during the whole fruit development, especially the content of anthocyanin after veraison. While the SM had higher content of flavonols such as quercetin, kaempferol and their derivatives. The expression of anthocyanin-related genes such as UFGT, OMT, GST, MATE, MYBA1, and MYBA2 was remarkably higher in SB than those in SM, which may attribute to higher anthocyanin content, while the higher expression of F3H and FLS resulted higher level of flavonols in SM. These results improve our understanding of flavonoid profiles and molecular mechanism in table grape cultivars.     

蓝莓花青素生物合成相关基因表达与分子进化分析

运用实时聚合酶链式反应方法,测定8个品种的蓝莓(包括6个高丛蓝莓:绿宝石、蓝美1号、海岸、莱格西、比洛克西、奥尼尔;2个兔眼蓝莓:括灿烂、园蓝)花青素合成途径中的VcCHS、VcCHI、VcF3H、VcDFR、VcANS结构基因及转录因子MYB基因相对表达量,分析其对花青素合成的调控作用.结果 表明:VcCHS、VcC...     

“紫娟”茶中的EGCG3"Me成分研究

"紫娟"是云南大叶群体种中的一种稀有茶树品种,因富含花青素成分其新鲜嫩梢的芽、叶、茎均呈现紫色,从而具有很高的科研价值和经济开发潜力,当今其功能化学成分的研究已成为了茶学研究热点之一。本文采用HPLC以及LC-MS技术首次报道分析了茶树特异品种"紫娟"中的表没食子儿茶素-3-O-(3-O-甲基)没食子酸酯(EGCG3"Me)成分及高EGCG3"Me含量"紫娟"茶的加工工艺。结果表明,茶树特异品种"紫娟"鲜叶中含有EGCG3"Me成分(含量为1.05%);在一芽五叶新梢不同嫩度的鲜叶中,第三叶的EGCG3"Me含量最高(含量为1.24%);采用蒸青绿茶或者晒青绿茶的加工工艺可以使成茶有效保留鲜叶中的EGCG3"Me成分。此外,还分析比较了普通炒青绿茶与"紫娟"绿茶中主要儿茶素成分的含量差异,发现较高的ECG和EC含量而较低的EGCG含量是茶树特异品种"紫娟"绿茶中儿茶素组成的主要特点。     

‘红富士’苹果气调贮藏期间果皮色泽变化及花青苷合成相关基因相对表达量的差异比较

研究采收时苹果果皮颜色对气调贮藏期间果皮色泽及花青苷合成相关基因相对表达量的影响,为苹果贮藏保鲜提供理论依据。以2种不同色泽的‘红富士’苹果为试材,采用色差仪、紫外分光光度计和荧光定量聚合酶链式反应法分别测定贮藏期间果皮色值、花青苷、叶绿素含量及花青苷相关合成基因的相对表达量变化。贮藏过程中,花青苷含量出现波动变化,其中着色好的苹果果皮中花青苷含量下降幅度为51.36%~69.51%,而着色差的苹果花青苷含量下降幅度为74.45%~95.30%;着色好的叶绿素含量下降显著高于着色差的苹果。采收时着色好的苹果果皮中花青苷合成相关基因除LDOX外,相对表达量均显著高于着色差的苹果;随着贮藏时间的延长,2种不同色泽的苹果果皮中花青苷合成相关基因的相对表达量均显著降低;但在贮藏后期着色差的苹果果皮中CHI、F3H、DFR、ANR相对表达量显著高于着色好的苹果。随着贮藏时间的延长,花青苷合成相关基因的相对表达量显著降低,导致花青苷合成速率下降,花青苷降解,果实发生果皮褪色现象。采收时着色差的‘红富士’苹果在气调贮藏期间比着色好的苹果更容易发生果皮褪色现象。     

H NMR-based metabolomic characterization during green tea (Camellia sinensis) fermentation

The metabolic behavior of green tea (Camellia sinensis) during tea fermentation was characterized by ¹H NMR spectroscopy coupled with multivariate statistical analysis to provide comprehensive information on changes in metabolites induced by tea fermentation. Fourteen tea metabolites of epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), epigallocatechin-3-gallate (EGCG), theanine, alanine, acetate, quinate, glutamate, caffeine, sucrose, glucose, and gallate, as identified by ¹H NMR spectroscopy, were responsible for metabolic differentiation between green tea and fermented tea by principal component analysis. During tea fermentation, levels of EC, EGC, ECG, EGCG, quinate, caffeine, and sucrose were decreased, whereas gallate and glucose levels were increased. In particular, unique changes in caffeine and gallate levels were observed during tea fermentation, which caffeine and gallate levels have been shown to vary after tea fermentation among many reports to date. This study highlights that metabolomics with global profiling and a highly reliable and reproducible ¹H NMR spectroscopic data set can provide a better understanding of unique changes in tea metabolites during tea fermentation.     

茶多酚EGCG通过调控miR-16-5p/含铜胺氧化酶1轴发挥对过氧化氢诱导的人心肌细胞凋亡的保护作用

目的:探究茶多酚表没食子儿茶素没食子酸酯（EGCG）对过氧化氢（H₂O₂）诱导人心肌细胞HCM凋亡的保护作用中的分子机制。方法:利用H₂O₂建立HCM细胞凋亡模型;通过caspase-3活性检测实验评价细胞凋亡水平;利用CCK-8法检测药物的细胞毒性;qPCR和Western blot用于检测含铜胺氧化酶1（AOC1）和miR-16-5p的表达水平;通过细胞转染调控AOC1和miR-16-5p在HCM细胞中的表达;通过TargetScan预测以及双荧光素酶报告基因实验验证miR-16-5p和AOC1 mRNA 3'UTR区的结合关系以及结合位点。结果:EGCG处理后可以显著抑制H₂O₂诱导的HCM细胞凋亡（P<0.05）;在凋亡细胞中,AOC1表达显著下降,EGCG可以显著上调AOC1的表达,而敲减AOC1显著逆转EGCG对凋亡的抑制（P<0.05）;同时,在凋亡细胞中,miR-16-5p表达显著上升,EGCG可以显著抑制miR-16-5p的表达,而上调miR-16-5p显著逆转了EGCG对凋亡的抑制（P<0.05）;上调miR-16-5p显著逆转了EGCG对凋亡细胞中AOC1表达的促进;最后,miR-16-5p可以靶向抑制AOC1的表达,而过表达AOC1显著逆转了miR-16-5p诱导的HCM细胞凋亡。结论:EGCG通过调控miR-16-5p/AOC1轴发挥了对H₂O₂诱导HCM细胞凋亡的保护作用,同时提示AOC1是保护心肌细胞损伤治疗的潜在新靶点。