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。     

黄烷醇类化合物的药理活性研究进展

黄烷醇类化合物是一类常见的天然植物多酚类化合物包括儿茶素类、花色素类及黄酮类等化合物,大部分存在于多种木本植物组织中,如山楂、葡萄、可可粉、苹果及草莓等,与日常的饮食有着非常密切的联系。近年以来,国内外许多学者对黄烷醇类化合物进行了研究,多项研究结果表明黄烷醇类化合物具有多种保健功能及生物活性作用,如清除自由基、抗氧化、抗肿瘤、抗炎、抗真菌、降血脂、保护肝脏、保护心血管等,也已被很多的药物科学研究所证实,并成为当今开发研究的热点。本文主要对天然黄烷醇类化合物的来源及多种药理活性等作用进行了综述,并对我国黄烷醇类化合物开发的应用前景提出了一些建议,对黄烷醇类化合物取代合成药物应用于保健食品等行业提供了较好的参考。     

葡萄及葡萄酒生理活性物质的研究概况(Ⅰ)生理活性物质概况

葡萄或葡萄酒中含有大量生理活性物质，其中主要为诸多酚类化合物。目前已明确葡萄或葡萄酒的生理活性效果大多与此类化合物相关。葡萄或葡萄酒中的酚类化合物主要有类黄酮类、原花色素类(即浓缩单宁类)、白藜芦醇类以及酚酸类。其中，主要类黄酮有黄酮醇以及黄烷酮醇类、儿茶素类(异黄酮醇，黄烷-3-醇)以及花色苷类。本概述了葡萄以及葡萄酒中的诸多酚类化合物的化学结构以及含量，这对于葡萄功能性食品的开发具有一定的参考价值。     

茶多酚保健功能研究

茶多酚（Tea Polyphenots）是茶叶中多酚类物质的总称，包括黄烷醇类、花色苷类、黄酮类、黄酮醇类和酚酸类等。其中以黄烷醇类物质（儿茶素）最为重要。茶多酚又称茶鞣或茶单宁，是形成茶叶色香味的主要成份之一．也是茶叶中有保健功能的主要成份之一。     

酚类物质和可溶性蛋白对苹果浓缩汁后混浊的影响

测定了鲁加1号和鲁加5号苹果浓缩汁在贮藏过程中可溶性蛋白质含量、总酚含量、黄烷醇类多酚含量、缩合单宁含量和几种小分子酚类物质的含量的变化。结果表明:苹果浓缩汁中总酚含量、可溶性蛋白含量以及缩合单宁的含量随着贮藏时间的延长而降低,而黄烷醇类多酚的含量则是呈先降低然后又上升的趋势,小分子酚类物质则因苹果品种的不同和小分子酚类物质的不同存在很大的差异,但总体的变化呈下降趋势。相关性分析表明:可溶性蛋白含量、黄烷醇类多酚含量和表儿茶素的含量与浊度值呈极显著正相关,咖啡酸的含量与浊度值呈显著正相关,阿魏酸的含量与浊度值呈显著负相关;在贮藏过程中黄烷醇类多酚、咖啡酸和表儿茶素含量的变化量与浊度值的变化量呈极显著负相关,可溶性蛋白含量的变化量与浊度值的变化量呈显著负相关。     

苹果酒酚类物质研究进展

苹果酒中含有多种酚类物质,主要是酚酸类和类黄酮类化合物,酚酸类包括绿原酸、原儿茶酸和p-香豆酸等,类黄酮类主要是黄烷-3-醇类,包括儿茶素、表儿茶素等.这些成分对苹果酒的风味、颜色和质量起着重要作用.综述了苹果酒中的酚类化合物及其作用机理,并简要介绍了酚类物质的测定方法.     

黄烷-3-醇类化合物在体内的吸收、代谢特征与机制研究进展

黄烷-3-醇类化合物是人类饮食中含量最丰富的膳食多酚之一,近年来,黄烷-3-醇类化合物备受关注,这主要是因为许多研究发现其与很多慢性疾病风险的降低和代谢综合征的缓解密切相关,但黄烷-3-醇类化合物在体内发挥的作用一定程度上取决于其被摄入后的吸收和代谢,尤其是肠道微生物的分解代谢。因此,本文将重点探讨黄烷-3-醇类化合物的吸收、代谢及其生物转化的途径,有助于揭示其在体内的生物学作用。     

黄酮类化合物的保健作用

黄酮类化合物(Flavonoids),又称生物类黄酮(Bioflavonoids),早期是指具有乙一苯基吡喃酮结构的一类黄色素,现指具有色酮环与苯环为基本结构的一类化合物的总称。可以分类为:黄酮类、黄酮醇类、异黄酮类、黄烷酮类等,广义的范围还包括查耳酮、嗅酮、异黄烷酮、双黄酮(Biflavonoids)及茶多酚(儿茶素的结构、性质及作用与类黄酮相似,也可归于黄酮类化合物中),其中黄酮醇是重要的一类。一、黄酮类化合物的摄入量及在食物中的含量(一)类黄酮在部分食物中的含量果蔬中黄酮类化合物几乎以配糖体形式存在,且含量较低,如洋葱、土豆、包心菜、芹菜、…     

荔枝核中黄烷-3-醇的鉴定及原花青素的提取

采用95%（V/V）、50%（V/V）醇提荔枝核,经石油醚、乙酸乙酯、正丁醇依次萃取后,再利用硅胶柱层析等方法分离纯化,得到化合物Ⅰ,通过理化性质和波谱技术,鉴定为黄烷-3-醇类化合物表儿茶素.原花青素是由多羟基黄烷-3-醇单元构成的低聚体和多聚体,由不同数量的儿茶素或表儿茶素结合而成,通过单因素实验和L16（45）正交实验,确定原花青素的最佳提取工艺.最佳提取条件为：乙醇浓度50%,浸提温度60℃,料液比1：20（W/V）、浸提时间3h.最佳条件下收率为5.05%.     

不同溶剂对酿酒葡萄皮渣多酚组成的提取效果比较

为测定不同极性溶剂对酿酒葡萄皮渣中5类非花色苷多酚的提取效果,分别采用乙酸乙酯、丙酮、甲醇、水作为提取溶液,通过HPLC-MS/MS检测葡萄皮和葡萄籽中31种非花色苷多酚的组成和含量。通过比较4种提取溶液的提取效果,发现甲醇对各类非花色苷多酚的提取效果最好;有机溶剂对黄酮醇类、黄烷-3-醇类、芪类多酚的提取效果较好;水对苯甲酸类、肉桂酸类酚酸的提取效果较好。比较酿酒葡萄皮和籽中非花色苷多酚差异,发现葡萄皮中最主要非花色苷酚为黄酮醇类、苯甲酸类,葡萄籽主要多酚为黄烷-3-醇类,而肉桂酸类和芪类多酚在葡萄皮渣中含量最少;酿酒葡萄皮渣中含量较高的多酚单体为杨梅素、儿茶素、表儿茶素、没食子酸、香草酸。由此推论酿酒葡萄皮和葡萄籽中多酚组成有一定差异,且其提取效率和分子结构、溶液极性等因素有关。     

益智酮A与姜黄色素的抗氧化性与其构效的关系

运用分子力学和量子化学计算的方法,研究益智酮A与其类似物姜黄色素抗氧化性的构效关系。从电荷、键长和生成热之差分析益智酮A与姜黄色素的抗氧化性,结果表明益智酮A的姜黄色素因具有相同的结构而具有类似的抗氧化性,但因所带的电荷和生成热之差不同而存在抗氧化性强弱的差异。     

Mass spectrometry fragmentation pattern of coloured flavanol‐anthocyanin and anthocyanin‐flavanol derivatives in aged red wines of Rioja

Background and Aims: During wine ageing, a great variety of reactions take place, resulting in an immense variety of products whose structure sometimes remains unknown. The aim of this work is the study of different fragmentation patterns of flavanol‐anthocyanin derivatives formed along the wine ageing; these patterns are useful for elucidating the different structures of these compounds and other new related ones. Methods and Results: Several wines from the Protected Denomination of Origin Rioja have been studied by an analytical method that combines column chromatography and high‐performance liquid chromatography with diode array and mass and tandem mass spectrometric detections. Thirty‐five coloured flavanol‐anthocyanin compounds formed by direct reaction or by acetaldehyde‐mediated condensation have been identified. For direct reaction derivatives, two different fragmentation patterns (one of them not previously reported) have been observed depending on the position of flavanol in the coloured derivative. Several compounds have been identified in aged wines for the first time to the authors' knowledge, like (+)‐gallocatechin‐cyanidin‐3‐glucoside and (+)‐catechin‐cyanidin‐3‐glucoside Conclusions: The developed analytical procedure has allowed the identification of some compounds for the first time, and two different fragmentation patterns have been observed depending on the position of flavanol in the pigment. Significance of the Study: The establishment of different fragmentation patterns allows the structural elucidation of unknown compounds.     

Electronic polarizability as a predictor of biodegradation rates of dimethylnaphthalenes. an ab initio and density functional theory study

Geometries, relative stabilities, electronic excited states, atomic charges, and electronic dipole polarizabilities of dimethylnaphthalene (DMN) isomers have been calculated in gas and aqueous phases by ab initio and DFT methods. At the highest levels of calculation, alpha,alpha-DMN (2,6-DMN, 2,7-DMN, and 2,3-DMN) are the lowest energy isomers, while 1,8-DMN is the less stable by 7-8 kcal mol(-1). The averaged electronic polarizability, , is dependent on the position of the methyl substituents, increasing in the order alpha, alpha-DMN < (a, beta-DMN < beta, beta-DMN, with the largest values being obtained for 2,6-DMN and 2,7-DMN, while the lowest value is calculated for 1,8-DMN isomer. Polarizability differences among the isomers have been related to their spectroscopic properties. The computed value of DMN isomers, with the notable exception of 2,7-DMN, is in excellent linear relationship with the observed first-order biomass-normalized rate coefficient, a parameter related to the rate of biodegradation of polycyclic aromatic hydrocarbons (PAHs). This result suggests that electronic polarizability may be a useful tool for prediction of biodegradation trends of series of compounds, and inductive and dispersive interactions play a fundamental role in the biodegradation process of DMNs. The present approach is potentially suitable for applications on PAHs with higher molecular weight.     

Formation of methyl glyoxal in dihydroxyacetone and glycine Maillard reaction: A computational study

By considering the formation of methyl glyoxal as one of the possible intermediates, mechanisms for the intermediate stage of the Maillard reaction of dihydroxyacetone and glycine under different pH conditions have been proposed, following the Hodge-scheme. Density functional theory calculations have been performed at the standard state on the proposed mechanisms to calculated the Gibb’s free energy changes for the formation of different compounds in different steps of the reaction. Thus, the possibility for the formation of different compounds in the proposed mechanisms has been evaluated. Electronic energy changes for the formation of different compounds in the proposed mechanisms have been calculated to observe the internal energy changes of the reaction. The total mass balance has been followed during the calculation of electronic and Gibb’s free energies. The result reveals that methyl glyoxal is one of the most likely intermediates in the reaction, and dihydroxyacetone + deprotonated glycine and dihydroxyacetone + unprotonated glycine reactions are assumed favorable for the production of methyl glyoxal. The gaseous phase reaction is supposed to be more feasible than the aqueous phase reaction for the production of methyl glyoxal. Glyceraldehyde + protonated glycine and glyceraldehyde + glycine zwitterion reactions are postulated as less feasible for the formation of methyl glyoxal.     

Study on chemical composition and biological activities of essential oil and extract from Salvia pisidica

In this study, total contents of phenolic, flavanol and flavonol, antioxidant activities and antimicrobial activities of the Turkish endemic Salvia pisidica Boiss. & Heldr. ex Bentham (Lamiaceae) extract and essential oil were assessed in vitro. Total phenolic, flavanol and flavonol contents in the extract were 54.57 mg gallic acid equivalents (GAE)/g, 16.70 mg catechine equivalents (CE)/g and 18.19 mg rutin equivalents (RE)/g, respectively. Antioxidant activities (IC₅₀ value) of the extract and essential oil were determined as 4.88 and 6.41 mg/mL by DPPH assay, respectively. 31 compounds were determined in the essential oil using GC-MS and the major compounds (%) were camphor (23.76), sabinol (19.2), α-thujone (14.2) and eucalyptol (1.8-cineole) (5.8).The antimicrobial activity of the methanolic extract and the essential oil against 13 bacterial and two yeast strains was determined. The extract (concentration 5 g/100 ml or 10 g/100 ml) was effective against most of the strains tested, yet not against Bacillus cereus, Staphylococcus aureus, Aeromonas hydrophila and the two yeast strains tested. The essential oil (2 g/100 ml) showed an antimicrobial effect against all the gram (+) bacteria tested, against Saccharomyces cerevisiae, but was not effective against all gram (−) bacteria and Candida albicans. These results show that S.piscidica essential oil and extract could be considered as a natural alternative to traditional food preservatives and be used to enhance food safety and shelf life.     

Reaction Between Malvidin 3-Glucoside and (+)-Catechin in Model Solutions Containing Different Aldehydes

ABSTRACT: The contribution of the aldehyde composition of wine spirit to the color changes in Port red wine was studied in model solutions. Malvidin 3-glucoside was shown to be very reactive towards catechin in the presence of different aldehydes: acetaldehyde, isovaleraldehyde, benzaldehyde, propionaldehyde, isobutyraldehyde, formaldehyde, and 2-methylbutyraldehyde. LC/MS data confirmed the formation of oligomeric pigments resulting from the reaction between the anthocyanin and the flavanol (colored products) and between 2 flavanol units (colorless products) mediated by each aldehyde assayed. The UV-visible spectra of the colored pigments showed a λ_max bathochromically shifted relatively to the λ_max of original anthocyanins. All samples revealed a "blueing" and "darkening" color effects using the CIELAB system.     

岷江百合与兰州百合鳞茎中多酚组分及其生物活性

为研究百合的抗氧化和抑菌活性,以野生岷江百合和兰州百合为材料,采用比色法、高效液相色谱法(HPLC)和比浊法对其鳞茎中总多酚、黄酮、黄烷醇、单体酚组分及含量、抗氧化能力和抑菌活性进行分析。结果表明:两种百合鳞茎中均富含多酚但种间存在显著差异(p<0.05),岷江百合鳞茎中总多酚、黄酮和黄烷醇的含量分别是兰州百合含量的2.07、2.25、3.16倍;在两种百合鳞茎中检测出14种单体酚,其中原矢车菊素B2含量最高,在岷江百合和兰州百合中分别达到了37.60、20.60 mg·kg-1,除没食子酸外,岷江百合鳞茎中其他被检测出的单体酚含量是兰州百合的1.43~41.84倍;两种百合鳞茎多酚提取物均具有一定的抗氧化和抑菌活性,且岷江百合的抗氧化和抑菌活性均显著高于兰州百合(p<0.05),是兰州百合的1.40~14.40倍。野生岷江百合鳞茎多酚提取物具有抗氧化和抑菌双重作用,可作为天然抗氧化剂、抗菌药物应用于食品和医药业,具有良好的开发应用前景。     

Biotransformation of phenolics (isoflavones,flavanols and phenolic acids) during the fermentation of cheonggukjang by Bacillus pumilus HY1

Changes in β-glycosidase, esterase activities, isoflavone, flavanols and phenolic acid during the fermentation of Korean whole soybean fermented food cheonggukjang by Bacillus pumilus HY1 were investigated. The levels of aglycones, flavanols and gallic acid increased, while the β-glucosidase activity, esterase activity, glycosides content (except for acetylglycosides) and flavanol gallates decreased. Total isoflavone content slightly decreased after 60 h of fermentation, while total flavanol and phenolic acid content increased. The highest levels of daidzein (aglycone type) and acetyldaidzin (glycoside type) were recorded after 48 h of fermentation. The levels of catechin, epicatechin and gallic acid also increased during fermentation. However, total contents of glycosides, malonylglycosides and flavanol gallates decreased by about 80%, 90% and 60% during 60 h of fermentation, respectively. In addition, total phenolic content increased markedly during fermentation, while levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity increased. Hence, it would be beneficial for the food industry if components of cheonggukjang could be separated and developed into functional products.     

Preservation of Cocoa Antioxidant Activity, Total Polyphenols, Flavan-3-ols, and Procyanidin Content in Foods Prepared with Cocoa Powder

ABSTRACT:  Little is known about the effects of common cooking processes on cocoa flavanols. Antioxidant activity, total polyphenols (TP), flavanol monomers, and procyanidin oligomers were determined in chocolate frosting, a hot cocoa drink, chocolate cookies, and chocolate cake made with natural cocoa powder. Recoveries of antioxidant activity, TP, flavanol monomers, and procyanidins ranged from 86% to over 100% in the chocolate frosting, hot cocoa drink, and chocolate cookies. Losses were greatest in the chocolate cake with recoveries ranging from 5% for epicatechin to 54% for antioxidant activity. The causes of losses in baked chocolate cakes were investigated by exchanging baking soda with baking powder or combinations of the 2 leavening agents. Use of baking soda as a leavening agent was associated with increased pH and darkening color of cakes. Losses of antioxidant activity, TP, flavanol monomers, and procyanidins were associated with an increased extractable pH of the baked cakes. Chocolate cakes made with baking powder for leavening resulted in an average extractable pH of 6.2 with essentially complete retention of antioxidant activity and flavanol content, but with reduced cake heights and lighter cake color. Commercially available chocolate cake mixes had final pHs above 8.3 and contained no detectable monomeric flavanols after baking. These results suggest that baking soda causes an increase in pH and subsequent destruction of flavanol compounds and antioxidant activity. Use of an appropriate leavening agent to moderate the final cake pH to approximately 7.25 or less results in both good leavening and preservation of cocoa flavanols and procyanidins.