Antioxidant properties of lucerne extracts

Aqueous extracts of fresh and dehydrated lucerne were found to exhibit heat-stable antioxidant activity toward the autoxidation of linoleic acid, the lipoxidase-catalysed oxidation of linoleic acid and the lipoxidase-induced carotene oxidation. EDTA increased the antioxidant activity of lucerne extract in all three systems. Alone, EDTA inhibited linoleate autoxidation, but not lipoxidase-catalysed linoleate oxidation, and was only partly inhibitory toward lipoxidase-induced carotene oxidation. The presence of ferulic acid in the acid hydrolysate of lucerne extract could be demonstrated by both paper and gas chromatography. This acid, and the related coumaric and sinapic acids, were shown to inhibit lipoxidase activity. It is suggested that a ferulic acid derivative may play a rôle in the antioxidant effects observed with aqueous lucerne extracts.     

Effect of phenolic acids on glucose and organic acid metabolism by lactic acid bacteria from wine

The influence of phenolic (p-coumaric, caffeic, ferulic, gallic and protocatechuic) acids on glucose and organic acid metabolism by two strains of wine lactic acid bacteria (Oenococcus oeni VF and Lactobacillus hilgardii 5) was investigated. Cultures were grown in modified MRS medium supplemented with different phenolic acids. Cellular growth was monitored and metabolite concentrations were determined by HPLC-RI. Despite the strong inhibitory effect of most tested phenolic acids on the growth of O. oeni VF, the malolactic activity of this strain was not considerably affected by these compounds. While less affected in its growth, the capacity of L. hilgardii 5 to degrade malic acid was clearly diminished. Except for gallic acid, the addition of phenolic acids delayed the metabolism of glucose and citric acid in both strains tested. It was also found that the presence of hydroxycinnamic acids (p-coumaric, caffeic and ferulic) increased the yield of lactic and acetic acid production from glucose by O. oeni VF and not by L. hilgardii 5. The results show that important oenological characteristics of wine lactic acid bacteria, such as the malolactic activity and the production of volatile organic acids, may be differently affected by the presence of phenolic acids, depending on the bacterial species or strain.     

Free radical scavenging capacity and inhibition of lipid oxidation of wines,grape juices and related polyphenolic constituents

The antioxidant activity of grape juices, wines made from the same lot as juices and their major polyphenolic constituents was measured by the inhibition of lipid oxidation (ferric-thiocyanate) and free radical scavenging (2,2-diphenyl-1-picrylhydrazyl) methods. dl-α-Tocopherol and 3-tertiary-butyl-4-hydroxyanisole (BHA) were used as references. The inhibition of lipid oxidation of the standards followed the order: rutin = ferulic acid > tannic acid = gallic acid = resveratrol > BHA = quercetin > dl-α-tocopherol > caffeic acid. Meanwhile, the free radical scavenging activity of gallic acid was the highest, tannic acid, caffeic acid, quercetin, BHA and rutin activities were intermediate and that for ferulic acid, dl-α-tocopherol and resveratrol were the lowest. Wines had higher activity than the corresponding grape juices and red wine showed the strongest activity among the grape products tested. The antioxidant activity of the samples seems to be based on their free radical scavenging capacity.     

Extraction and purification of ferulic acid from flax shives,wheat and corn bran by alkaline hydrolysis and pressurised solvents

Extraction of ferulic acid and vanillin from flax shives, wheat bran and corn bran were carried out using two extraction methods, non-pressurised alkaline hydrolysis (0.5 M NaOH) and pressurised solvents (0.5 M NaOH, water, ethanol and ammonia). There were no differences in the content of products extracted with non-pressurised and pressurised 0.5 M NaOH solution yielding mostly ferulic acid, p-coumaric acid and small amounts of vanillin. Pressurised low-polarity water (PLPW), pressurised aqueous ethanol (PAE) and pressurised aqueous ammonia (PAA) were efficient in the one-step production of vanillin from ferulic acid in flax shives (guaiacyl-rich), wheat bran and corn bran (ferulic acid-rich). Vanillin was produced from the bound-ferulic acid via cleavage of the aliphatic double bond under the pressurised conditions. Higher content of ferulic acid in the corn bran yielded higher amounts of vanillin compared to wheat bran and flax shives. A simple and efficient purification procedure for ferulic acid from the alkaline extracts is presented. This procedure exploits the solubility of ferulic acid at different ethanol concentrations.     

Treatment of methyl tert-butyl ether contaminated water using a dense medium plasma reactor: a mechanistic and kinetic investigation

Plasma treatment of contaminated water appears to be a promising alternative for the oxidation of aqueous organic pollutants. This study examines the kinetic and oxidation mechanisms of methyl tert-butyl ether (MTBE) in a dense medium plasma (DMP) reactor utilizing gas chromatography-mass spectrometry and gas chromatography-thermal conductivity techniques. A rate law is developed for the removal of MTBE from an aqueous solution in the DMP reactor. Rate constants are also derived for three reactor configurations and two pin array spin rates. The oxidation products from the treatment of MTBE-contaminated water in the DMP reactor were found to be predominately carbon dioxide, with smaller amounts of acetone, tert-butyl formate, and formaldehyde. The lack of stable intermediate products suggests that the MTBE is, to some extent, oxidized directly to carbon dioxide, making the DMP reactor a promising tool in the future remediation of water. Chemical and physical mechanisms together with carbon balances are used to describe the formation of the oxidation products and the important aspects of the plasma discharge.     

Non-isothermal autohydrolysis of nixtamalized maize pericarp: Production of nutraceutical extracts

Nixtamalized maize pericarp (NMP) was subjected to isothermal processing in aqueous media, and the amount and composition of the solid and liquid phases were determined. The major reaction products were arabinoxylo-oligosaccharides (AXOS). The maximum release of AXOS (39.6 g/100 g NMP) was achieved operating at 207 °C. Ferulolyl substituents of AXOS accounted for 77% of the total ferulic acid contained in the feedstock. Autohydrolysis liquors were extracted with ethyl acetate, and the phenolic compounds present in the organic phase were identified and quantified. The antioxidant activity of extracts (measured by reducing power and radical scavenging activity) compared favorably with the ones of commercial antioxidants. On the basis of the experimental results, it can be concluded that the obtained feruloylated AXOS can be used as food ingredients with potential to cause health benefits (including prebiotic effects and prevention of harmful oxidation reactions).     

Use of Nitrobenzene Oxidation for Study of Lignin Composition with an Improved Method for Product Extraction,

Sample stability, extraction procedures and solvents and various gas chromatographic procedures were studied in an attempt to improve procedures for the determination of lignin by the nitrobenzene oxidation technique. Extraction of oxidation products with ether, although needed to extract p-coumaric acid, resulted in a marked decrease in sample stability and increased extraneous material. Studies using a variety of phases and sample preparations showed that with 5% OV-25 on Gas Chrom Q the peaks corresponding to caffeic and ferulic acids were largely or entirely azoxybenzene and p-phenylazophenol. The introduction of disposable diatomaceous earth columns for extracting oxidation products resulted in a faster procedure and the removal of the by-products azoxybenzene and p-phenylazophenol from the extracted products.     

Antioxidative properties of aqueous and aroma extracts of squid miso prepared with Aspergillus oryzae-inoculated koji

To evaluate the antioxidative properties of a newly developed fermented paste (squid miso) prepared from squid mantle flesh with Aspergillus oryzae-inoculated koji, we used in vitro models, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, nitric oxide (NO) and carbon-centered radical-scavenging activity (RSA), reducing power ability (RPA), and linoleic acid oxidation. The antioxidant activity of volatile compounds, which were extracted from squid miso by dichloromethane, was confirmed based on the results obtained by the oxidation models consisting of carotene linoleate and hexanal. The RSA of the miso against several radicals, including DPPH, hydroxyl, nitric oxide and carbon-centered radicals measured by ESR spectrometry increased gradually through the fermentation period. On the other hand, the RPA increased rapidly in early stages of fermentation. Proteins were hydrolyzed to peptides and amino acids during fermentation. Certain peptides of low molecular mass significantly contributed to RSA. 4-Ethylguaiacol in the RSA active fraction, which was obtained by column chromatography, was the most potent antioxidative in the volatile extract. Analysis of phenolics in ethyl acetate fraction clearly suggested that 4-ethylguaiacol in the squid miso is possibly a bioconversion product of ferulic acid derived from koji. However, the aqueous extracts containing antioxidative peptides contributed more remarkably to radical scavenging than heterocyclic volatiles and phenolics.     

Proposed mechanism for the degradation of pelargonidin 3-glucoside by caffeic acid o-quinone

Caffeic acid o-quinone (CQ) was prepared by oxidation of caffeic acid with o-chloranil in organic media. The reaction between the purified CQ and pelargonidin 3-glucoside (Pg 3-glc, non-o-diphenolic anthocyanin) was monitored by HPLC and spectrophotometric analysis. Quantitative analyses were performed to establish the stoichiometry of the reactions. The results showed that Pg 3-glc reacted with the hydroxycaffeic acid o-quinone formed by dismutation of CQ in aqueous media. This reaction led to the formation of condensation products with a stoichiometry close to 1:1. The degradation products were isolated by gel filtration on Sephadex G-25. The UV-vis spectra and chemical analysis of the degradation products suggested that they contained both caffeic acid (or secondary products of oxidation) and anthocyanin moieties. HPLC analysis showed that the purified fractions contained several degradation products.     

Colour properties,stability, and free radical scavenging activity of jambolan (Syzygium cumini) fruit anthocyanins in a beverage model system: Natural and copigmented anthocyanins

The colour and stability properties of jambolan anthocyanins, both natural and copigmented forms, were investigated in beverage model as well as their radical scavenging ability. Natural anthocyanins of jambolan revealed low colour intensity due to glycosylation structure of the anthocyanins as diglucoside. The intermolecular copigmentation of anthocyanins with sinapic acid, caffeic acid, ferulic acid, and rosemary polyphenolic extract could enhance the colour intensity, which was observed through spectrometric parameters, such as hyperchromic effect (ΔA_vis-max) and bathochromic shift (Δλ_vis-max). In addition of sinapic acid, caffeic acid, and rosemary polyphenolics also increased the stability of the anthocyanin colour during exposure to white fluorescent light and storage at refrigeration and room temperatures, whereas on high thermal treatments, this phenomenon was not observed. Furthermore, beverage model coloured with natural or copigmented anthocyanins revealed DPPH radical-scavenging activity. The AEAC values indicated that the beverage models with copigmented anthocyanins had higher scavenging activity than the beverage with natural anthocyanins.     

考氏科萨克氏菌产阿魏酸酯酶条件优化、酶学性质及其初步应用

以考氏科萨克氏菌（Kosakonia cowanii）为试验菌株,对其产酶条件、酶活性质以及初步应用进行研究。结果表明,最佳产酶条件为装液量90 mL/250 mL、培养基初始pH值为5.5、接种量4%、温度34 ℃。在此优化条件下,酶活为28.27 U/L,比优化前提高了20.92%。该酶最适反应温度、pH值分别为 50 ℃、5.6,在30～40 ℃及pH 5.0～6.8范围内稳定性良好。将该菌株应用到麸皮、大曲和糟醅中,麸皮中发酵至第7天时阿魏酸含量比最初提高了22.42%,糟醅中阿魏酸含量呈先增后减趋势,大曲中阿魏酸含量呈递增趋势,表明添加菌株有利于释放麸皮、糟醅和大曲中的阿魏酸。     

有机相脂肪酶催化合成阿魏酸乙酯

本实验研究了有机溶剂中脂肪酶催化阿魏酸乙酯合成反应。对催化合成阿魏酸乙酯反应的脂肪酶和反应介质进行了比较,最佳溶剂为叔丁醇,在所选的6种脂肪酶中,固定化于大孔丙烯酸树脂的南极假丝酵母脂肪酶B(Novozym 435)的催化活性最好。同时对影响合成阿魏酸乙酯反应的因素(底物浓度、底物摩尔比、温度、初始水含量、反应时间等)进行了探讨,优化了反应条件:在10ml无水叔丁醇中,当酸醇摩尔比为1:1,酸浓度为0.1mol/L,反应温度为60℃,反应时间为120h时产率达到最高,脂肪酶Novozym 435具有较高的稳定性,重复使用六次后产率仍然可达到23%。     

Color enhancing effect of carboxylic acids on anthocyanins

The color enhancing effect of aromatic and aliphatic carboxylic acids on anthocyanin-glucosides was investigated in this work. The color of black rice anthocyanin-rich fraction was successfully improved after the addition of aromatic acids (p-coumaric acid, ferulic acid, and sinapic acid), aliphatic acid (lipoic acid) and tannic acid (as a complex acid). The addition of carboxylic acids showed an enhancing and stabilizing effect on the color of black rice juice during storage, which was observed through changes in CIELAB and spectrophotometric parameters. Sinapic, ferulic, and p-coumaric acids enhanced the color of black rice juice the most, with the highest efficiency for the dimethoxylated cinnamic acid derivate (sinapic acid). New anthocyanin-derived pigments were first isolated through silica gel TLC and identified using Maldi-Mass spectrometry at m/z values of 613, 659, 673, and 639, respectively, for vinylpyranoanthocyanins formed after adding coumaric, ferulic, sinapic, and lipoic acids. Based on these experimental results, the addition of carboxylic acids in an anthocyanin-rich fraction can be used as an efficient tool for their color enhancement and stability.     

粪产碱菌对阿魏酸厌氧降解的影响

粪产碱菌在以阿魏酸为唯一碳源的厌氧发酵中培养7 d,阿魏酸的降解率约为70%;研究秸秆厌氧发酵产气（以产气量反应菌群的活性）发现,体系接种5%粪产碱菌后,菌群的活性最强,生物气增量最大,达130 mL,比接种3%和7%粪产碱菌的体系提高85.71%和116.67%;同时体系的产酸效率和阿魏酸的降解率均显著提升,分别比接种3%和7%粪产碱菌的体系提高136%和110.71%以及25%和33.33%。傅里叶红外光谱检测表明：厌氧发酵体系接种5%粪产碱菌后秸秆中木质素、阿魏酸的特征官能团结构被有效破坏。秸秆厌氧发酵体系接入粪产碱菌可以有效降解阿魏酸等木质素降解衍生物、解除木质素及其降解产物对厌氧菌群的毒性同时提高产气效率,具有应用价值。     

Demethylation of Ferulic Acid and Feruloyl-arabinoxylan by Microbial Cell Extracts

The O -demethylation of ferulic acid and feruloyl-arabinoxylan by the anaerobic bacteriaClostridium methoxybenzovorans (strain SR3) and the facultative aerobic bacteria Enterobacter cloacae (strain DG6) was investigated in order to produce caffeic acid and caffeoyl-arabinoxylan. As both strains produced endocellular enzymes, disrupted cell extracts from these two bacteria were prepared and tested. The SR3-disrupted cell extract was able to produce caffeic acid from free ferulic acid with 84% yield. The use of cysteine as reducing agent in the reaction medium stabilised the highly reactive caffeic acid produced. The DG6-disrupted cell extract used ferulic acid but no caffeic acid was detected, suggesting that it was only an intermediary product of the reaction. None of the two disrupted cell extracts were able to O-demethylate feruloyl-arabinoxylans.     

Kinetic changes and antihypertensive effect of aqueous extract of Danggui (Angelica sinensis radix) after stir-fry processing

Danggui (Angelica sinensis Radix) in East Asia for its unique pleasant flavor is usually cooked before utilizing to enhance its tonic effect. To evaluate the quality and bioactivity changes, heat treatments were carried out at 250°C for 0–45 min. 5-Hydroxymaltol, 5-hydroxymethylfurfural, Z-ligustilide, and ferulic acid in aqueous extract of processed danggui (APD) were determined by HPLC while antihypertensive effects were studied after oral administration of APD (50 and 100 mg/kg) for 3 days in spontaneously hypertensive rats (SHR). Compared with aqueous extract of danggui (AD), contents of ferulic acid and Z-ligustilide in APD were significantly decreased but 5-hydroxymaltol and 5-hydroxymethylfurfural were increased. APD could lower blood pressures, plasma renin activities, and angiotensin II levels of SHR, but AD failed to do those. APD exhibited hypotensive effects by regulating renin-angiotensin system and may warrant further evaluation as a potential antihypertensive agent.     

有机酸对紫甘薯花色苷的辅色作用

辅色作用是一种提高花青素稳定性的有效途径。研究柠檬酸、DL-苹果酸、酒石酸、咖啡酸和阿魏酸对紫甘薯花色苷的辅色作用。结果表明,5 种有机酸均能提高紫甘薯花色苷的吸光度,但均没有改变紫甘薯花色苷的组分。90 ℃条件下,柠檬酸、DL-苹果酸和酒石酸可使紫甘薯花色苷的半衰期由15.3 h分别提高到19.1、19.0 h和16.9 h;咖啡酸与阿魏酸显著地降低了紫甘薯花色苷热稳定半衰期,分别降至1.8 h和1.6 h,不利于紫甘薯花色苷的热稳定性。     

挤出过程中板栗全粉-瓜尔胶-阿魏酸复合体系的加工特性变化

板栗产品的营养与品质可由板栗全粉的加工及消化特性决定,该研究提出利用挤出处理协同常见食品添加剂瓜尔胶及阿魏酸对板栗全粉进行改性,对其冻融稳定性、吸水性、吸油性、流变学特性以及体外消化特性进行了系统探究。结果显示,挤出协同瓜尔胶提高了板栗全粉的冻融稳定性、吸水性及水溶性,降低了吸油性、起糊温度,增大了崩解值并可调控其糊稳定性。在流变性质方面,挤出协同瓜尔胶作用有助于提高板栗全粉储藏过程中的凝胶刚性,但随着其添加量的增加凝胶刚性减弱。而进一步向体系中引入阿魏酸会增大峰值黏度、起糊温度、崩解值,但对板栗全粉的冻融稳定性、吸水性、水溶性、吸油性影响较小。同时挤出协同3 wt.%瓜尔胶及3 wt.%阿魏酸可使板栗全粉的抗消化组分增加27.00%~32.10%。研究结果表明挤出协同瓜尔胶及阿魏酸处理可有效改变板栗全粉的加工特性,可为新型板栗食品的创制提供基础数据。     

Peroxidase-active cell free extract from onion solid wastes: biocatalytic properties and putative pathway of ferulic acid oxidation

The exploitation of food residuals can be a major contribution in reducing the polluting load of food industry waste and in developing novel added-value products. Plant food residues including trimmings and peels might contain a range of enzymes capable of transforming bioorganic molecules, and thus they may have potential uses in several biocatalytic processes, including green organic synthesis, modification of food physicochemical properties, bioremediation, etc. Although the use of bacterial and fungal enzymes has gained attention in studies pertaining to biocatalytic applications, plant enzymes have been given less consideration or even disregarded. Therefore, we investigated the use of a crude peroxidase preparation from solid onion by-products for oxidizing ferulic acid, a widespread phenolic acid, various derivatives of which may occur in food wastes. The highest enzyme activity was observed at a pH value of 4, but considerable activity was retained up to a pH value of 6. Favorable temperatures for increased activity varied between 20-40 degrees C, 30 degrees C being the optimal. Liquid chromatography-mass spectrometry analysis of a homogenate/H(2)O(2)-treated ferulic acid solution showed the formation of a dimer as a major oxidation product.     

In vitro and in vivo antioxidant properties of ferulic acid: A comparative study with other natural oxidation inhibitors

Ferulic acid exhibits a wide range of therapeutic effects that are attributed to its potent antioxidant capacity. However, in vitro antioxidant properties of ferulic acid have not been elucidated in detail. Evidence that polyphenols, including ferulic acid, act as antioxidants in vivo is also limited. In order to elucidate in more detail the scientific background of antioxidant activities of ferulic acid, we carried out in vitro and in vivo experiments. We focused on superoxide anion scavenging activity, xanthine oxidase inhibition activity, and chain-breaking activity. The combined antioxidant activity from radical scavenging and xanthine oxidase inhibition of ferulic acid was much weaker than that of (−)-epigallocatechin gallate (EGCG) and ascorbic acid. On the other hand, EGCG, ascorbic acid and ferulic acid exhibited chain-breaking activity and prevented ischaemia-reperfusion-associated intestinal injury. Chain-breaking activity may play a contributory role in the protective effect of ferulic acid on oxidative injury in humans and in in vivo studies.