黑小麦麸皮酚酸物质的定性分析与阿魏酸含量测定

对黑小麦麸皮中的主要酚酸物质进行制备和定性分析,并测定阿魏酸含量。采用乙醇和氢氧化钠溶液处理黑小麦麸皮,提取样品中的游离态酚酸(free phenolic acids,FPA)和结合态酚酸(conjugated phenolic acids,CPA)。通过液质联用(LC/MS)和紫外光谱(UV)等方法对提取的酚酸物质进行定性分析。紫外光谱显示,游离态和结合态酚酸具有与阿魏酸相似的分子结构。LC/MS检测结果显示,游离态和结合态酚酸的相对分子质量分别为224和194。由此判断黑小麦麸皮中的游离态酚酸FPA主要为芥子酸,结合态酚酸CPA主要为阿魏酸。采用高效液相色谱(HPLC)对黑小麦麸皮中的结合态阿魏酸含量进行测定。结果表明,紫粒黑小麦麸皮的阿魏酸含量为2.07 mg/g,与蓝粒黑小麦麸皮的阿魏酸含量(2.12 mg/g)相近,其含量高于当地种植的普通小麦麸皮的阿魏酸含量(1.17 mg/g)。     

不同种类啤酒的酚酸含量和抗氧化特性

本文研究了不同品种啤酒的总多酚含量、游离和总酚酸含量及抗氧化能力。啤酒中酚酸含量最多的是阿魏酸,其次为芥子酸、香草酸、咖啡酸、对香豆酸、4-羟基苯乙酸;阿魏酸、咖啡酸、紫丁香酸、芥子酸和香豆酸主要以结合形式存在,对香豆酸和4-羟基苯乙酸以游离和结合形式存在。在不同类型啤酒中总多酚和酚酸的存在方式不同,用FRAP法评价不同啤酒的抗氧化能力也有显著差异。严格说来,FRAP值与多酚和酚酸含量有一定的相关性。本文也研究了用FAPR法评价单体酚酸的抗氧化能力。     

荞麦蜜酚酸含量的高效液相色谱测定及其抗氧化作用的研究

以中国产荞麦蜜为原料,采用高效液相色谱-电化学检测法(HPLC-ECD)测定其中的原儿茶酸、没食子酸、咖啡酸、丁香酸、p-香豆酸、绿原酸、阿魏酸和鞣花酸等8种酚酸的含量。结果表明,中国荞麦蜜中含有原儿茶酸、没食子酸、咖啡酸、p-香豆酸、阿魏酸等五种酚酸,其含量分别为没食子酸为461μg/100g蜂蜜,p-香豆酸为150μg/100g蜂蜜,咖啡酸为79μg/100g蜂蜜,原儿茶酸为30μg/100g蜂蜜,阿魏酸为39μg/100g蜂蜜。本文还对荞麦蜜酚酸提取物的抗氧化作用进行了研究,结果显示荞麦蜜酚酸提取物对超氧阴离子自由基、羟基自由基、DPPH自由基和脂质过氧化均有抑制作用。     

模型反应中不同酚酸物质抑制PhIP形成效果分析

2-氨基-1-甲基-6-苯基-咪唑[4,5-b]吡啶（2-amino-1-methyl-6-phenyl-imidazole[4,5-b]pyridine,PhIP）是食品加工和烹饪中含量较高且有致癌风险的杂环胺类化合物。该文在以苯丙氨酸和肌酐为前体物质的模型体系中,考察阿魏酸、咖啡酸、对香豆酸3种单体酚酸以及混合酚酸对PhIP形成的抑制效果,并进一步探讨酚酸类物质在模型体系中对PhIP形成的抑制效果是否存在相互协同作用。结果表明,在单体酚酸模型中,当酚酸浓度为10-10mg/mL或10-9mg/mL时,从整体效果比较3种单体酚酸对PhIP形成的抑制效果,由强到弱分别为咖啡酸、对香豆酸、阿魏酸,而当酚酸浓度为10-8mg/mL时,阿魏酸对PhIP形成的抑制效果强于对香豆酸;在混合酚酸模型中,阿魏酸+对香豆酸的组合对PhIP形成抑制效果最强,抑制率为56.37% ,咖啡酸+对香豆酸的组合对PhIP形成抑制效果最弱,抑制率为13.33% 。推测其反应机理可能是酚酸类物质与前体物质发生反应生成新的化合物,消耗掉前体物质的量,从而抑制模型体系中PhIP的形成。     

HPLC法同时测定采后莲雾果实木质素代谢途径中5种酚酸的含量

为探讨采后莲雾果实贮藏期间酚酸含量变化对果实木质化代谢的影响,建立高效液相色谱法同时测定采后木质素代谢途径中5种酚酸(肉桂酸、对香豆酸、咖啡酸、阿魏酸、芥子酸)的方法。采用InfinityLab Poroahell C18色谱柱为固定相,以甲醇和乙酸溶液(p H 2.4)为流动相进行梯度洗脱,流速为0.8 mL/min,柱温25℃,紫外检测器于波长279 nm和320 nm处进行检测。各酚酸组分的线性范围较宽,相关系数均大于0.999 4,检出限为0.01～0.03 mg/kg,定量限为0.03～0.09 mg/kg,相对标准偏差小于5%,加标回收率为86.18%～99.05%。该方法准确度、灵敏度高,操作简便,适用于采后莲雾果实木质素代谢途径中5种酚酸的同时测定。测得莲雾贮藏期间肉桂酸、对香豆酸、咖啡酸、阿魏酸和芥子酸的含量范围分别为11.46～24.69、0.92～1.45、2.31～5.32、8.86～20.58 mg/kg和9.48～22.62 mg/kg。     

不同酿酒高粱酚类物质含量测定及抗氧化活性比较

以6种酿酒高粱籽粒为研究对象,分别比较其游离态与结合态总酚、总黄酮、酚酸物质种类及含量,并对其抗氧化活性进行 分析。 结果表明,不同酿酒高粱品种游离态总酚、总黄酮;结合态总酚、总黄酮含量分别在135.47～274.38 mgGAE/100 g、94.60～ 148.31 mg/100 g;618.27～1 383.17 mgGAE/100 g、123.06～434.84 mg/100 g。 酿酒高粱籽粒中游离态酚酸以阿魏酸、丁香酸与没食 子酸为主,平均含量分别为611.19 μg/g、380.66 μg/g、359.34 μg/g;结合态酚酸以阿魏酸、丁香酸为主,平均含量为1 608.33 μg/g、 376.78 μg/g。 酿酒高粱籽粒中游离态与结合态总酚ABTS抗氧化能力值分别占总ABTS能力值14.6%与85.4%;酿酒高粱籽粒中游离 态与结合态总酚FRAP抗氧化能力值占总FRAP能力值14.3%与85.7%。 酿酒高粱籽粒具有丰富的酚类物质,良好的抗氧化活性,且品 种间有显著性的差异（P＜0.05）。     

野生蓝莓酚酸成分鉴定及其清除细胞内自由基活性研究

酚酸具有良好的自由基清除活性,能有效降低非酒精性脂肪肝、心血管疾病、糖尿病等疾病发生风险。酚酸是大兴安岭野生蓝莓的主要酚类物质之一,其成分尚不清楚。本文采用柱层析法纯化蓝莓中的酚酸组分,用高效液相色谱法进行成分鉴定与含量检测。以AAPH诱导Hep G-2细胞氧化损伤模型评价酚酸清除细胞内自由基活性。从物质结构特性出发,通过循环伏安法分析酚酸的氧化-还原能力,探讨酚酸清除细胞内自由基活性机理。结果表明:蓝莓酚酸主要由咖啡酸、绿原酸、肉桂酸、阿魏酸、没食子酸、对香豆酸和原儿茶酸7种酚酸组成,含量较多的为绿原酸(21.2%)、阿魏酸(8.3%)、对香豆酸(7.0%)和咖啡酸(4.6%)。4种主要酚酸对细胞内自由基清除能力为咖啡酸绿原酸阿魏酸对香豆酸,其失电子能力依次为绿原酸咖啡酸阿魏酸对香豆酸。酚酸是蓝莓的主要抗氧化成分之一,其失电子能力是影响酚酸清除细胞内自由基活性的主要原因。     

小麦酚酸提取工艺优化及产区与品种差异对酚酸含量的影响

研究NaOH浓度、液料比、乙酸乙酯萃取时间和萃取次数对小麦籽粒中酚酸提取量的影响,并优化提取条件;运用高效液相色谱-质谱联用法分析不同产区主栽小麦品种差异对酚酸含量的影响。结果表明：NaOH浓度、液料比、乙酸乙酯萃取时间和萃取次数对小麦籽粒中酚酸提取量影响显著,经响应面优化获得小麦籽粒中酚酸提取条件为：NaOH溶液浓度1.56 mol/L、液料比15.53∶1（mL/g）、萃取时间17.33 min、萃取2 次。在此提取条件下,小麦籽粒中酚酸提取量达到1 055.99 mg/kg。小麦中主要有9 种酚酸,分别为没食子酸、原儿茶酸、4-羟基苯甲酸、香草酸、咖啡酸、丁香酸、p-香豆酸、芥子酸和阿魏酸,其中阿魏酸为主要酚酸,占总酚酸的73.07%～89.01%。江淮麦区宁麦14中总酚酸含量最高,达1 001.12 mg/kg,与该产区的保麦6号、淮麦33有显著性差异;黄淮麦区的新麦26中总酚酸含量最高,为1 016.03 mg/kg,与该产区的矮抗58、百农207有显著性差异。由此可见,不同产区主栽小麦品种的差异对酚酸含量的影响极大。     

贵州蓝莓蜜的成分分析及其抗氧化活性

以贵州蓝莓蜜为研究对象,对其理化指标、抗氧化活性、多酚成分进行研究。结果显示,贵州蓝莓蜜酸度值44.69 mmol/kg,总糖含量79.30%,葡萄糖含量(40.88%)高于果糖含量(38.41%);总酚酸和总黄酮含量分别为20.27～24.72 mg GAE/100 g和3.88～6.77mg RE/100 g,DPPH和ABTS自由基半抑制率分别为119.04～136.56 mg/mL和140.56～212.34 mg/mL;蓝莓蜜含15种多酚类物质(原儿茶酸、对羟基苯甲酸、香草酸、咖啡酸、对香豆酸、芦丁、阿魏酸、杨梅酮、木犀草素、桑色素、槲皮素、芹菜素、山奈酚、异鼠李素、高良姜素),其中,黄酮类物质含量最高为槲皮素,酚酸含量由高到低为:对羟基苯甲酸对香豆酸阿魏酸咖啡酸香草酸原儿茶酸。研究表明,蓝莓蜜酸度偏高、易结晶,结合槲皮素含量高的特点与酚酸含量高低规律,可作为蓝莓蜜鉴定与检测的参考指标。     

不同晚熟柑橘中酚类物质的含量检测及分析

采用超高效液相色谱(ultra-performance liquid chromatography,UPLC)对9种晚熟柑橘(沃柑、春见、大雅柑、不知火、默科特、红肉脐橙、伦晚脐橙、红翠2号和塔罗科血橙)中的主要酚类物质(13种类黄酮和7种酚酸)进行测定,分析比较不同品种柑橘果皮、果肉和果汁(柑橘原汁)中酚类物质种类和含量的差异。结果表明:9个柑橘品种的果皮、果肉、果汁中,类黄酮均以橙皮苷为主,酚酸以阿魏酸为主,且果皮中多甲氧基黄酮含量丰富。在9个柑橘品种果汁中,春见的橙皮苷、咖啡酸含量最高。果肉中,沃柑中阿魏酸、咖啡酸、芥子酸含量最高,塔罗科血橙的橙皮苷、对香豆酸含量最高。果皮中,默科特的芸香柚皮苷、川皮苷、阿魏酸含量最高。杂柑果皮中咖啡酸、阿魏酸及川皮苷含量高于橙类。晚熟柑橘含有丰富的酚类物质,并呈现显著的多样性。     

A comparative study on free and bound phenolic acid content and their antioxidant activity in bran of rice (Oryza sativa L.) cultivars of Eastern Himalayan range

In our study, seven most prevailing but unexplored indigenous rice cultivars of northeast India, situated in the Eastern Himalayan Range, were investigated for their phenolic acid profile, total phenolic content (TPC) and antioxidant capacities in free and bound phenolic extracts of their bran. HPLC studies showed the presence of ferulic, p‐coumaric, sinapic, caffeic, chlorogenic and vanillic acids, with ferulic and p‐coumaric acids being the dominant phenolic acids in the bound form. The lower EC₅₀ values of the bound extracts than the free extracts suggested the better radical scavenging activity of the bound extracts. Significant correlations were observed between TPC and phenolic acid content (HPLC‐DAD) of bound extracts, and between Trolox equivalents antioxidant capacity (TEAC) and phenolic acid content (HPLC‐DAD) of both free and bound extracts. The findings suggest that phenolic acids in the rice cultivars investigated were exclusively present in bound form and contribute significantly towards their antioxidant capacity.     

Distribution of bound and free phenolic acids in oranges (Citrus sinensis) and Grapefruits (Citrus paradisi)

Free phenolic acids may be the precursors for vinyl phenols and off-flavours formed in citrus products during storage. Quantitative determination of free and bound phenolic acids in fruit parts of grapefruit (Citrus paradisi Macfadyen) and oranges (Citrus sinensis (L) Osbeck) was performed by extraction with ethyl acetate, silica gel column chromatography and HPLC analyses of samples before and after alkaline hydrolysis. The content of free and bound phenolic acids was further determined in juice derived from fruit harvested early, mid and late in season. As found previously for ferulic acid, phenolic acids occur mainly in bound forms in grapefruits and oranges. In both fruits the peels contained the major portion of cinnamic acids compared with the endocarp, and the flavedo was richer in hydroxycinnamic acids than the albedo. In most cases, hydroxycinnamic acid content was in the following order: ferulic acid>sinapic acid>coumaric acid>caffeic acid. Results showed that the content of bound cinnamic acids was unchanged or slightly elevated from early to late season. However, the content of free acids was reduced during that period.     

Production of coumaric acid from sugarcane bagasse

Phenolic acids were released from sugarcane bagasse by alkaline hydrolysis at 30 °C for 4 h; The alkaline hydrolysates were ultrafiltrated, the permeates purified with anion exchange resin. The phenolic acids bound by the resin were desorbed by a mixture of water–ethanol–HCl solution (36: 60: 4) after washing the resin with water, ethanol and dilute HCl respectively. The combined eluents were concentrated for crystalization, and the crystals filtered and washed using 1% (v/v) HCl. After this purification process, the purity of products reached 89.7% based on coumaric acid. Results of HPLC/MS, HPLC using standard coumaric acid and ferulic acid showed that the main component of the purified bagasse hydrolysate was p-coumaric acid rather than ferulic acid. The purified products showed the same antioxidant activity, reducing power and free radical scavenging capacity as the standard p-coumaric acid.The technology could be applied on industrial scale.Industrial relevanceThis research presents a technology to produce coumaric acids from sugarcane bagasse. The first step is to release coumaric acid by alkaline hydrolysis. The second step is to remove the viscous polysaccharides and protein by ultrafiltration. The third step is to purify coumaric acid from the permeate of ultrafiltration by anion chromatography, and the alkaline could be reused to hydrolyze the bagasse. The technology showed potential application on industrial scale.     

几种酚酸对木聚糖酶活力的影响

采用3,5-二硝基水杨酸法(DNS法)测定酶解后还原糖释放量,研究4种不同酚酸(阿魏酸、对-香豆酸、水杨酸、单宁酸)对木聚糖酶活力的影响。结果表明:阿魏酸、对-香豆酸、水杨酸能提高木聚糖酶活力,当这3种酚酸质量浓度为0.75mg/mL时,酶活力分别提高65.59%、46.21%和12.83%。单宁酸抑制木聚糖酶活性,添加量为0.50mg/mL时,抑制率达37.18%。动力学研究表明:上述4种酚酸均能提高酶与底物的亲和力,对-香豆酸能提高酶反应速度,但单宁酸会使反应速度显著降低。     

Phenolic compounds in peanut seeds: Enhanced elicitation by chitosan and effects on growth and aflatoxin B1 production by Aspergillus flavus

Effects of chitosan and Aspergillus flavus to enhance elicitation of phenolic compounds in viable peanut seeds were conducted at two water activity levels. In vitro effects of phenolic acids on A. flavus growth and aflatoxin B₁ production were also studied. Chitosan enhanced elicitation of free phenolic compounds (FPC) at Aw .85 and .95 levels. A. flavus initially decreased and subsequently increased FPC content, but bound phenolic compounds (BPC) decreased during incubation. Chitosan + A. flavus treatment caused an increase in FPC reaching a plateau between 24–48 h at Aw .85 while BPC levels increased over the same period at both Aw levels. Major free and bound phenolic acids detected were p‐coumaric, ferulic and an unknown phenolic acid eluting at a retention time of 22 min. Generally, chitosan significantly enhanced elicitation of free ferulic and p‐coumaric acids and bound p‐coumaric acid at Aw .95. Free unknown phenolic and bound ferulic acids at Aw .85 were enhanced by chitosan. A. flavus caused significant induction of bound p‐coumaric and ferulic acids and free unknown phenol at Aw .85. Chitosan + A. flavus enhanced free p‐coumaric (3 h) and unknown phenolic acids and bound p‐coumaric acid at Aw .95 while bound ferulic acid was enhanced at Aw .85. Chitosan limited A. flavus growth and subsequent aflatoxin production by inducing susceptible tissues to produce more preformed phenolic compounds.

Analysis of liquid cultures of A. flavus revealed that p‐coumaric, ferulic, and vanillic acids and a mixture of these phenolic acids slightly inhibited mycelial growth. Production of aflatoxin B₁ by A. flavus was completely inhibited at 1 mM and 10 mM concentrations of the phenolic acids and their mixture on four days of incubation. Mode of action of phenolic acids is likely on the secondary pathway for aflatoxin B₁ production and not on the primary metabolism for fungal growth.     

Addition of phenolic acids on the reduction of methanol content in wine

ABSTRACT:  Utilization of phenolic acids, including gallic acid, coumaric acid, caffic acid, cinnamic acid, and ferulic acid, for methanol reduction in wine was investigated. Enzyme activities of pectinesterase and pectin lyase decreased significantly when 0.1 mg/L of gallic acid, coumaric acid, caffic acid, cinnamic acid, or ferulic acid was added. However, no inhibition on polygalacturonase activity was observed when 0.5 mg/L of phenolic acid was added. Methanol content in commercial pectic enzyme (CPE) group increased from 11.53 ± 1.34 to 56.67 ± 3.75 ppm in the final products. Adding gallic acid or coumaric acid with CPE inhibited the increase of methanol production. In addition, when 0.2 mg/L of phenolic acid (gallic acid or coumaric acid) was added, the amount of total phenolic acid released from CPE + gallic acid or CPE + coumaric acid groups became higher than CPE group by approximately 466 and 539 mg/L, respectively. In conclusion, the values of lightness, red content, yellow content, total pigment, and total phenolic acid increased in the presence of gallic acid or coumaric acid with CPE, suggesting that adding gallic acid or coumaric acid into winemaking process is a potential method for reducing methanol content, improving wine quality, as well as increasing healthy compounds in wine production.     

Characterisation of black cumin,pomegranate and flaxseed meals as sources of phenolic acids

The article focuses on the extraction of ten phenolic acids from black cumin (Nigella sativa L.), pomegranate (Punica granatum L.) and flax (Linum usitatissimum L.) seed meals. The extracts have been fractionated as free, esterified and insoluble‐bound phenolic compounds and quantitatively determined by HPLC–PDA. The analysed meals can be utilised for obtaining valuable phenolic acids. However, the distribution of phenolic compounds varies depending on the meal source. The insoluble‐bound fraction has been the richest for the black cumin meal, both qualitatively and quantitatively, containing all ten analysed phenolics. In the pomegranate meal, the main phenolic has been gallic acid, accounting for nearly 48% in free form. The esterified form of the flaxseed meal has been abundant with ferulic (1025.44 ± 3.99 mg kg^?1 dry weight), caffeic and p‐coumaric acids. The total amount of phenolic acids would be underestimated if only free fractions would be taken into account, while neglecting esterified (for the pomegranate and flax meals) and insoluble‐bound fractions (for the black cumin and pomegranate meals).     

苯丙氨酸-肌酐模型反应体系中甘蔗糖蜜酚酸单体对PhIP的抑制作用

该研究探讨了模型反应体系中甘蔗糖蜜含有的阿魏酸和香草酸对2-氨基-1-甲基-6-苯基-咪唑[4,5-b]吡啶(Ph IP)的抑制作用。实验通过糖蜜净化处理方法去除糖蜜中的胶体、灰分和重金属等物质,得到糖蜜粗提物,建立没食子酸标准曲线,测定糖蜜提取物中多酚含量。通过UPLC-MS对糖蜜提取物进行分析,确定糖蜜提取物中含有的酚酸种类。将酚酸单体分别加入到模型反应(苯丙氨酸和肌酐)体系中,用UPLC-MS系统分析模型反应中Ph IP的变化。结果发现,糖蜜提取物中多酚含量多达3.58 mg/g,通过和酚酸标准品对照,发现糖蜜提取物中含有阿魏酸和香草酸。在模型反应体系中,随着阿魏酸和香草酸浓度的增加,模型反应中苯丙氨酸含量和Ph IP的生成量均先逐渐减少后趋于平稳,当阿魏酸溶液浓度达到2.33×10-7 g/m L时,对Ph IP的抑制效果最佳,总体抑制率为76.67%;当香草酸溶液浓度达到2.02×10-7 g/m L时,对Ph IP的抑制效果最佳,总体抑制率为77.43%。综上,甘蔗糖蜜中含有的阿魏酸和香草酸单体在模型反应体系中均对Ph IP有较强的抑制作用,为后续对Ph IP抑制物的研究提供了基础。