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This study monitors variations in isotopes and elements in relation to grape variety, environmental factors and provenance in order to address the wine authenticity issue. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) assessed the wines’ elemental content. Site-specific nuclear isotope fractionation-nuclear magnetic resonance and isotope ratio mass spectrometry methodologies determined in authentic and commercial wines the distribution of the naturally occurring stable isotopes of the deuterium/hydrogen (D/H) ratios and carbon (13C/12C) in ethanol of wine and oxygen ratio (18O/16O) in wine water. Chemometrics delineated the elements and isotopes responsible for wine classification. Specifically, unsupervised principal component analysis (PCA) framed the importance of grape variety and provenance, while supervised analysis pinpointed the vineyard effect and highlighted the contribution of the vintage year. Validation steps ensured that the extracted models do not predict randomly and their results are reliable. In fact, the acquired results can be incorporated to the EU Wine Isotopic Databank database providing both a guide and a tool for eventual candidatures for denomination of origin and support both Cypriot wine and winemakers. In this context, this research contributes to authenticity assurance of wines and adds value to final products, while it helps controlling hazards arising from environmental changes.

Extracts from three Salvia sp. (S. fruticosa, S. pomifera, and S. sclarea), native to the island of Crete, were fractionated using ethyl acetate and n-butanol and analyzed using liquid chromatography–diode array–mass spectrometry. The antioxidant potency of each fraction was assessed by the antiradical activity (AAR) and the hydroxyl free radical scavenging activity (SAHFR). The chromatographic analyses revealed a rich profile, composed of mainly of flavones, accompanied by a limited number of phenylpropanoids. The highest antioxidant activity was displayed by the n-butanol fraction of S. fruticosa, which also had the richest polyphenolic composition.

The purpose of this article was to investigate for the first time the nanoencapsulation of a naturally-occurring flavonoid, i.e. aureusidin, exhibiting a variety of properties including antioxidant. In particular, the encapsulation efficiency of aureusidin in biodegradable poly(lactic acid) PLA nanoparticles was evaluated using the emulsification-solvent evaporation technique, while some of the pertinent parameters affecting the properties of the formed nanoparticles were investigated. The obtained results were promising, suggesting that the particular polymer-technique system is a valid choice for aureusidin encapsulation and protection.

Introduction The bioactive metabolites derived from weeds have attracted the interest of the food and pharmaceutical industries due to their health benefits. Objective To evaluate the anti-oxidant and acetylcholinesterase activity of Dittrichia viscosa extracts and characterise the polyphenolic metabolites using the LC coupled with diode-array detection (DAD) and positive mode electrospray ionisation (ESI) MS method with a view to evaluating the exploitation potential of this invasive weed. Materials and methods Roots and aerial parts of D. viscosa were extracted with solvents of increasing polarity and their major polyphenolic metabolites were identified by LC − DAD/ESI(+)/MS. The total phenolic content of the extracts was determined using the Folin–Ciocalteu method, while their anti-oxidant activity was evaluated on the basis of their ability to scavenge the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide. Thin-layer chromatography was used to screen for acetylcholinesterase inhibitors. Results Stem extracts gave the highest phenolic content, whereas the roots showed the lowest content. Twenty-five polyphenolic constituents of the extracts were tentatively characterised according to their MS and UV spectroscopic data. Among the extracts studied, roots–ethyl acetate and flowers–diethyl ether revealed the highest activity according to the DPPH and chemiluminescence assays respectively. Conclusion The metabolic profile of D. viscosa was studied and the structures of the major polyphenolic metabolites were tentatively assigned based on their MS and UV–vis spectra. The extracts exhibited high levels of anti-oxidant and acetylcholinesterase inhibitory activity and the inhibitors are probably localised mainly in flowers and roots. Copyright © 2014 John Wiley & Sons, Ltd.

The goal of this work was to investigate the relationship between antioxidants' content and the oxidative stabilities of grape seed oils obtained from the Cabernet Sauvignon variety. The samples of grape seed oils were obtained by ultrasound assisted extraction. The time of extraction was varied, while the other relevant parameters: extraction temperature, solvent to solid ratio and sonication power were kept constant. For the sake of comparison, the extraction was also done using the conventional Soxhlet method. For all the oil samples obtained, the contents of total phenolic compounds (TPC), alpha-tocopherol and fatty acids were determined using relevant analytic methods. Importantly, in the present study, the modern analytical techniques for estimation of antioxidant capacity (measuring the chemiluminescence intensity of a luminol-hemin solution) and oxidative stability [differential scanning calorimetry (DSC), coupled with thermogravimetry (TG)] were proposed. The obtained results prove that ultrasonic irradiation enables effective extraction of grape seed oil. It was shown that the extractive yields and the amounts of total phenolic compounds and alpha-tocopherol increase with time of extraction; the optimum time was determined. Results obtained in this work show that, for both oxidative stability and antioxidant capacity, TPC have a more important role then alpha-tocopherol.

Grape seed extracts (GSEs) were investigated in yeast cells harbouring defects in their antioxidant system (regarding the cellular growth and growth recovery from H2O2 insult). GSEs antioxidant activity was detected in wild-type and mutant strains Δcta1, Δgsh1 and Δoye2glr1, while pro-oxidant activity in Δsod1 cells was seen. Assessment of proliferation of prostate cancer PC3 and HBV-replicating HepG2 2.2.15 cells treated with GSEs has shown higher cytotoxicity of red grape seed extract (RW) than white grape seed extract (WW) subjective to dose and period of administration. No antiviral effect was detected by measuring the secreted virion particles in HepG2 2.2.15 cells treated with GSEs. The GSEs play a dual antioxidant/pro-oxidant role in vivo according with the cellular antioxidant system deficiencies and exhibit cytotoxic properties in PC3 and HepG2 2.2.15 cell lines, but no antiviral action against HBV.

27 Páginas; 8 Figuras: 1 Tabla, Color quality is the economical key factor for oily extracts, also referred to as oleoresins, obtained from carotenogenic fruits and vegetables for application in foodstuffs. However, this organoleptic property is not the only attribute as carotenoids develop some bioactive actions, which provide a beneficial effect on health. It has been suggested that reaching some oxidation level during processing enhances the antioxidant activity of phytochemicals, including carotenoids, so that knowledge of the impact of thermal processing in the redox state and antioxidant activity is significant. During thermal degradation of carotenoids in tomato and paprika oleoresins the coloring content, redox state and antioxidant capacity were evaluated. The lipid profile and tocopherol content were similar in both oily extracts but significant differences were observed on functional properties derived from carotenoid activity. The initial antioxidant capacity was similar for both carotenoid extracts, tomato oleoresin kept higher antioxidant capacity values (DPPH test) than paprika oleoresin, although the degradation rate was significantly higher for lycopene, while carotenoids of paprika oleoresin degraded slowly. Paprika oleoresin showed a higher antioxidant activity (hydrogen peroxide test) than tomato oleoresin. Carotenoid degradation products may participate on radical scavenging reactions but efficiency depends on the radical species and structure of degradation products produced during thermal degradation., We wish to thank Mrs. S. Loupasaki for her technical help. This work was partially financed by the project AGL2007-60092/ALI (Ministerio de Educación y Ciencia, Spanish Government). D. Hornero-Méndez and A. Pérez-Gálvez are members of the IBERCAROT Network, funded by CYTED (ref. 112RT0445).

Sea buckthorn is a promising source of bioactive compounds. However, there is limited information on the effect of post harvest drying and extraction of sea buckthorn on its antioxidant capacity. The effect of freeze, air, and solar dryingon the extraction yield of sea buckthorn berries and leaves was evaluated with respect to their bioactive content. Sequential extraction with solvents of different polarity and solvent-free microwave-assisted extraction were applied. Freeze-drying has better performance in the berries’ extracts, while air-drying has better performance in the leaves’ extracts. All data were analyzed by Multi Factor Analysis of Variance (ANOVA) and Duncan's post-hoc tests at a level of α = .05. Although the extraction yield in the sequential extraction of sea buckthorn berries is significantly better, the leaves’ extracts exhibit superior radical scavenging ability. Accelerated solar drying appears to preserve sea buckthorn leaves without degrading their antioxidant content. The components...

The total phenolic content of methanol and ethyl-acetate extracts of pits from seven Algerian palm date (Phœnix dactylifera L.) fruit varieties was estimated by the Folin-Ciocalteau method. Their respective antioxidant activities were evaluated by the DPPH· and the Co(II)-EDTA luminol chemiluminescence tests and their phenolic profile was established by LC-DAD-MS (ESI− and ESI+). The total phenolic content of the methanolic extracts ranged from 27.2 to 38.5 mg of caffeic acid equivalents CAE/100 g fresh weight, while the ethyl acetate extracts gave contents ranging from 22.8 to 42.6 mg CAE/100 g fresh weight. The antiradical and the hydroxyl scavenging activities of the methanolic extracts were much higher than those of the ethyl acetate extracts. The different varieties that were studied did not show any major difference in their phenolic profile. Indeed, all the varieties contained mainly catechin or epi catechin derivatives, sinapic, cinnamic, and coumaric acid derivatives. However, it should be noted ...

In this study, the behaviour of catechin (Cat) and ascorbic acid (AA) and their mixtures at different ratios was studied in view of elaborating predictions over an eventual pro-oxidant or synergistic antioxidant activity. The Co(II)–EDTA luminol chemiluminescence showed that the mixture of Cat:AA (3:1) had the highest antioxidant activity, while the mixture of Cat:AA (1:2) the most pronounced pro-oxidant activity. As the concentration of AA increases, the antioxidant behaviour of the mixture increases strongly as well. The LC–MS analysis for the two mixtures (Cat:AA at ratios of 1:2 and 1:3) revealed that the sufficient of AA accounts for the good antioxidant behaviour of catechin (Cat:AA 1:3 with an IC50 of 47.61 ± 0.00 μM and the mixture Cat:AA 1:2 with an IC50 of 75.32 ± 0.86 μM as assessed by chemiluminescence), supported by the formation of structure I (m/z 183). As its concentration decreases, the antioxidant activity drops and this is attributed to the formation of structure II (m/z 255). However, when AA becomes lesser beyond this point, a re-strengthening of the antioxidant behaviour has been observed, which may be assigned to the formation of procyanidin structures. Thus, AA may suppress the formation of procyanidin, i.e. creation of C C bonds between the catechin units.

In the present study the biocatalytic activity of a crude onion peroxidase extract on the reaction between catechol and heterocyclic 1,3-dicarbonyl compounds is investigated. The crude enzyme preparation promotes effectively the reaction between catechol and 4-hydroxycoumarin, 4-hydroxy-1-methyl-2-quinolinone and 2,4-quinolinediol to afford the corresponding coumestans and benzofuroquinolinones in satisfactory yields. The products of the reaction are fully characterized spectroscopically and are found to possess potent antioxidant activity as evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and luminol-induced chemiluminescence assays.

The electrochemical behaviour of 13 chalcone analogues was systematically studied by means of cyclic voltammetry and chronoamperometry at a glassy carbon (GC), gold and platinum working electrodes using two different supporting electrolyte/solvent combinations. It was found that chalcone analogues can be easily oxidized at both GC and gold working electrodes, but not at a platinum electrode. Principal component analysis was further employed to reveal similarities/dissimilarities between oxidation potentials, chronoamperometric signals and ability of the compounds to scavenge the reactive oxygen species H2O2. The study reveals the inverse proportional relationship between the scavenging ability of H2O2, expressed as IC50, and chronoamperometric signal at 800 mV using gold as working electrode. Copyright © 2012 John Wiley & Sons, Ltd.

A series of (Z)-2-benzylidenebenzofuran-3-(2H)-ones (aurones) bearing a variety of substituents on rings A and B were synthesized and evaluated for their antiparasitic activity against the intracellular amastigote form of Leishmania infantum and their cytotoxicity against human THP1-differentiated macrophages. In general, aurones bearing no substituents on ring A (compounds 4a–4f) exhibit higher toxicity than aurones with 4,6-dimethoxy substitution (compounds 4g–4l). Among the latter, two aurones possessing a 2′-methoxy or a 2′-methyl group (compounds 4i and 4j) exhibit potent antileishmanial activity (IC50=1.3±0.1 μM and IC50=1.6±0.2 μM, resp.), comparable to the activity of the reference drug Amphotericin B, whereas they present significantly lower cytotoxicity than Amphotericin B as deduced by the higher selectivity index.

The behaviour of four known antioxidants (quercetin, ascorbic acid, catechin and caffeic acid) and their mixtures at different molar ratios was studied in view of elaborating predictions over an eventual pro-oxidant or synergistic antioxidant activity. The Co(II)–EDTA luminol chemiluminescence showed that the mixture of quercetin and ascorbic acid at ratio 2:1 had the most pronounced antioxidant activity, while that of quercetin and caffeic acid at ratio 1:2 showed the least antioxidant activity, which may be interpreted as a strong propensity for pro-oxidant behaviour. The LC–MS analysis for the two mixtures revealed a significant amount of unoxidised quercetin in the case of quercetin with ascorbic acid, whereas in the case of quercetin with caffeic acid this amount was negligible. This observation supports the fact that the first combination was more antioxidant than the second, through efficient quercetin recycling (reduction of the quinone by ascorbic acid; redox cycling of quinones).

Introduction Phytochemical analyses of weeds, many of which have been used in traditional medicine worldwide, could lead to the identification of secondary metabolites with significant biological activity. Objective To perform an assessment of the chemical composition and exploitation potential of the invasive weed Oxalis pes-caprae. To evaluate the anti-oxidant activity of its extracts and isolate and characterise polyphenolic metabolites using LC-DAD-MS (ESI+) and NMR methods. Methodology Aerial parts of the invasive weed O. pes-caprae were extracted with solvents of increasing polarity and their major polyphenolic metabolites were identified by LC-DAD-MS (ESI+). The total phenolic content of the extracts was determined using the Folin–Ciocalteu method, while their anti-oxidant activity was evaluated on the basis of their ability to scavenge the stable free radical 1,1-diphenyl-2-picrylhydrazyl and hydrogen peroxide. Results The major polyphenolic constituents of the extracts were tentatively characterised as chlorogenic acid, quinic ferulate, luteolin glucoside and cernuoside according to their MS and UV spectroscopic data. Cernuoside, an aureusidin glucoside, was isolated from the methanolic extract of the weed's flowers and its structure was unambiguously identified by 1D- and 2D-NMR spectroscopy. The butanol extract of O. pes-caprae displayed the highest anti-oxidant activity. Conclusion The metabolic profile of O. pes-caprae was studied and the structures of the major polyphenolic metabolites based on their MS and UV–vis spectra were tentatively assigned. The aureusidin glucoside cernuoside was isolated and characterised for the first time from O. pes-caprae. The extracts exhibited high levels of anti-oxidant activity. Copyright © 2012 John Wiley & Sons, Ltd.

High-performance liquid chromatography with confirmation by UV–visible photodiode array detector–positive electrospray ionization–mass spectrometry [HPLC-UV–vis-DAD-(+ESI)-MS] with enhanced fragmentation by appropriate adjustment of the cone voltage was used to determine bioflavonoid content of five citrus species (tangerine, sanguine, sour orange, lemon and grapefruit) cultivated in Greece which come from citrus varieties analyzed for the first time. The main groups of bioflavonoids found in the juice of the citrus species according to HPLC retention times, spectral data and literature references were O-glycosylated flavanones and flavones, C-glucosylated flavones, O-glucosylated flavones, O-C-glucosylated flavones like saponarin and a phenolic derivative. Copyright © 2012 John Wiley & Sons, Ltd.

The ability of a crude onion peroxidase preparation to act as a biocatalyst for the oxidative dimerization–cyclization of methyl p-coumarate, methyl caffeate and methyl ferulate is presented. The products of the reaction have been fully characterized and were found to possess potent antioxidant activity in a ferric reducing antioxidant power (FRAP) assay.

The electrochemical behaviour and the antioxidant effectiveness of ascorbic acid (AA), caffeic acid (CA), quercetin (Q), catechin (Cat), hesperetin (H) and their equimolar binary mixtures were evaluated by means of cyclic voltammetry and luminol Co(II)–EDTA chemiluminescence, respectively, with a view to the prediction of a potential prooxidant or synergistic behaviour of mixtures of antioxidants. An important synergistic oxidation between Q and Cat was observed. The mixture CA/AA manifested the most prooxidant tendency among all the tested compounds and their mixtures. AA increased the antioxidant activity of Q and decreased that of Cat. Q and Cat regenerated CA, the prooxidant effect of the mixtures increasing with less e-delocalisation. Cat and CA have an antagonistic effect. H has the closest oxidation potential to CA and a slight increase of its antioxidant activity was registered when mixed with CA, which was not the case when it was combined with the other compounds or measured alone.

In the framework of the detailed phytochemical analysis of the aerial parts of Sideritis syriaca, two novel acylflavones were isolated together with three acetylated flavone glycosides and acylated flavone glycosides. The novel acylflavones were identified as isoscutellarein 7-trans-p-coumarate and apigenin 7-,4′-bis(trans-p-coumarate). Their structures were elucidated by means of UV, 1D and 2D NMR, LC–DAD–MS and confirmed by HR-MS spectroscopy.

Truffles are one of the most prized of foods but also one of the most perishable. Storing fresh truffles entails the use of low temperatures and the addition of carbon dioxide, but the effect of carbon dioxide on truffle metabolism is largely unknown. Treatment with 50% CO 2 + 5% O 2 at 2 °C for 29 d caused a reduction in polyphenol contents and antioxidant activity compared to the controls (air treatment). ADH (alcohol dehydrogenase) and LDH (lactate dehydrogenase) activities in CO 2 -treated samples decreased together with the related metabolites, ethanol and lactic acid, but on day 29 (final sampling) they increased again, reaching the initial levels but still below the concentrations of air-treated samples. Polyamine contents decreased initially in CO 2 -treated samples more than in air-treated truffles but at the final sampling increased significantly (1.5–2.3-fold). In summary, polyphenol metabolism, anerobic pathways, and polyamine biosynthesis are reduced by high CO 2 and low O 2 atmospheres, suggesting reduced general cell metabolic activity associated with reduced senescent activity, or stress effects. The rapid increase of polyamines and anaerobic metabolism could be an index of the reaction to stress only at the end of storage, and the increase in polyamines could provide protection against pathogen attack.

The peel waste from two orange varieties (Valencia and Navel) was analyzed. The saponified extract was analyzed for the carotenoid content by thin-layer chromatography and high-performance liquid chromatography. Identification was made by ultraviolet-Vis spectrometry. Our studies revealed that the waste of Valencia orange peels is rich in apocarotenoids like 10′-apo-β-caroten-10′-ol, 10′-apo-β-caroten-10′-al, 8′-apo-β-caroten-8′-ol, 8′-apo-β-caroten-8′-al and 6′-apo-β-caroten-6′-ol representing more than 60% of the total carotenoids. Also identified were β-chryptoxanthin and, in minor quantities, dihydroxycarotenoids (zeaxanthin and its epoxides). β-Cryptoxanthin, which exhibits provitamin A activity, was the main compound in Navel variety extract. ζ-Carotene as well as some dihydroxy derivatives were also present. The amount of apocarotenoids in this variety is very low. The data reveal important differences of carotenoid composition depending on orange variety: Valencia variety was richer in short-chain apocarotenoids while Navel variety in nonpolar carotenoids. PRACTICAL APPLICATIONS The citrus fruit residues, remaining after juice extraction, represent approximately half of the wet mass of the whole fruit, including the peel (flavedo and albedo) and almost one-fourth of the whole fruit mass. Such a waste can be used as a good source for extracting bioactive molecules like carotenoid pigments, pectins and terpenes (essential oils). The technological applications given by the carotenoid composition of the orange peels may help the industrial processors to find new ways of increasing the profit by recuperating important bioactive molecules and also reducing the considerable problem of waste disposal. Such extracts can be very useful as functional additives for food matrices. The presence of ζ-carotene proves the fact that there is a great amount of phytoene in Navel variety, which is a compound commercially desirable, so the orange peel waste from Navel variety oranges can be taken as a commercial source of phytoene. β-Cryptoxanthin, which exhibits provitamin A activity, was also present. Its capacity to quench single oxygen and to be used as dairy product additive (e.g., butter colorant) is very useful in practice (medicine and food industry).

A range of fourty-six red grape (Vitis vinifera spp.) samples, originating from six widely cultivated varieties and covering major parts of the Hellenic vineyard, were assayed for their content in six principal anthocyanin pigments. Representative in vitro antioxidant parameters were also determined, including antiradical activity (A AR ), reducing power (P R ) and hydroxyl free radical scavenging activity (SA HFR ). Quantitative determination using high performance liquid chromatography showed that the prevalent pigment was malvidin 3-O-glucoside (average content 82.53 mg per 100 g fresh berry weight), followed by its coumarate derivative (29.26 mg per 100 g), paeonidin 3-0-glucoside (10.84 mg per 100 g), petunidin 3-0-glucoside (7.80 mg per 100 g) cyanidin 3-0-glucoside (5.67 mg per 100 g) and delphinidin 3-0-glucoside (1.28 mg per 100 g). The richest variety was Syrah, with total average anthocyanin content of 186.02 mg per 100 g, whereas the Hellenic native variety Xinomavro had the lowest average anthocyanin level (38.70 mg per 100 g). The establishment of correlations of individual and total anthocyanin contents with the values from the antioxidant test was accomplished with linear regression. The links of total anthocyanins were significant with all antioxidant parameters (P < 0.001), but more importantly with SA HFR (R 2 = 0.740). Malvidin 3-O-glucoside content had the higher correlation with SA HFR compared with all other anthocyanins (R 2 = 0.698, P < 0.001).

The polyphenolic composition of two Fortunella margarita (Nagami kumquat) specimens from Greece and Egypt was investigated employing fractionation by solvent partition and liquid chromatography-mass spectrometry. The main groups of phenolics identified in the different fractions generated were C-glycosylated flavones, O-glycosylated flavones, C-glycosylated flavanones, O-glycosylated flavanones, flavonols, chalcones, phenolic acids and derivatives thereof. The antioxidant potency of the fractions was assessed using two representative in vitro tests, including antiradical activity and hydroxyl free radical scavenging activity. It was revealed that the ethyl acetate fractions from both specimens contained the higher polyphenol content and exhibited the better antioxidant characteristics. The results indicated that F. margarita peels may be regarded as a rich source of potentially bioactive polyphenols.

Plant food residues including trimmings and peels might contain a range of enzymes capable of transforming bio-organic 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 interest in studies pertaining to biocatalytic applications, plant enzymes have been given less attention or even disregarded. In this view, this study aimed at investigating the use of a crude peroxidase (POD) preparation from onion solid by-products for oxidizing chlorogenic acid (CGA), a widespread phenolic acid, various derivatives of which may occur in foods and food wastes. The highest enzyme activity was observed at a pH value of 4, but considerable activity was also observed at pH 2. Favorable temperatures for increased activity varied between 5 and 20 °C. Liquid chromatography–mass spectrometry analysis of a POD-treated CGA solution showed the formation of two major oxidation products, which were tentatively identified as CGA dimers.

A 23-full factorial design and response surface methodology were deployed to assess some basic factors (time, % ethanol and pH) affecting profoundly the extractability of polyphenolic phytochemicals from grape (V. vinifera) seeds. In an effort to obtain a thorough insight into the applicability of the models established, seed extracts from three different varieties were tested, by determining several indices of the polyphenolic composition, such as total polyphenol (TP), total flavanol (TFl) and proanthocyanidin (PC) concentrations. It has been shown that the models generated can adequately predict the recovery levels for each polyphenol group, but the optimal conditions predicted for TP, TFl and PC recovery varied significantly. Notable differences were also seen among the different varieties. Correlation of the polyphenol indices with the antiradical activity and reducing power of the extracts indicated that there is no consistent pattern to associate specific polyphenol classes with the antioxidant potential, which might be an evidence of antagonism. Examination of the optimally obtained extracts using liquid chromatography-mass spectrometry revealed that the most prominent compounds were catechin, some flavanol dimers and galloylated derivatives thereof.

Olive mill waste water (OMWW) originating from a two-phase olive oil-producing plant was treated with a crude peroxidase extract prepared from onion solid by-products. The treatments were based on a 3 × 3 factorial design, employing a series of combinations of pH and H2O2, in order to identify optimal operational conditions. The treatment performance was assessed by estimating the removal percentage of total polyphenols. The model established produced a satisfactory fitting of the data (R2 = 0.94, p = 0.0158), while the second-order polynomial equation used to describe the process indicated that peroxidase-catalysed polyphenol removal in diluted OMWW is facilitated at relatively low pH and intermediate H2O2 values. A predicted value of 50.7 ± 9.5% removal was calculated under optimal operational conditions (pH 2.76, [H2O2] = 3.56 mM). Analysis of an untreated and an optimally treated sample by high performance liquid chromatography revealed that enzyme treatment brought about alteration in the original OMWW polyphenolic profile. The use of peroxidase from onion solid by-products is proposed as an alternative means that could have a prospect in bioremediation applications.

An experimental setup based on a 23-full factorial, central composite design was implemented with the aim to optimising recovery of polyphenols from onion solid wastes (OSW). In order to allow for the establishment of a sustainable process, reusable and non-toxic solutions composed of water/ethanol/citric acid were employed as extracting media. The factors considered were (i) the pH of the medium, (ii) the extraction time and (iii) the ethanol concentration. The model obtained produced a satisfactory fitting of the experimental data with regard to total polyphenol extraction (R2 = 0.97, p = 0.0025) and the reducing power of the extracts (R2 = 0.97, p = 0.0033), but not with the antiradical activity (R2 = 0.89, p = 0.0592). The 2nd order polynomial equations obtained after elaboration of the experimental data indicated that all parameters considered were significant in respect with the efficiency of total polyphenol recovery. The highest total polyphenol yield was theoretically predicted to be 9342 ± 1435 mg gallic acid equivalents per 100 g dry weight, under optimal conditions (60% EtOH, pH 2 and 4.2 h). Liquid chromatography-electrospray ionisation mass spectrometry of the optimally obtained extract revealed that the principal phytochemicals recovered were quercetin 3,4′-diglucoside, quercetin 4′-glucoside and quercetin. Simple linear regression analysis between the total polyphenol and the antiradical activity of the OSW extracts showed that there was no correlation in a statistically significant manner, as opposed to reducing power. Industrial relevance The recovery of value-added substances from agri-food industrial wastes is an issue with importance pertaining to both the reduction of the waste load released to the environment, and the development of novel, natural food additives with functional properties. Up to date, the examinations pertaining to the clarification of factors that can affect extractability were based on rather unilateral assessment, while it is generally accepted that the retrieval depends on several parameters, which render the phenomenon a particular complexity. In this view, the implementation of factorial design with respect to investigating in parallel several factors pertaining to efficient polyphenol recovery becomes imminent. Thus the establishment of models on such a sound experimental basis is expected to provide a reliable background for more costand resource-effective processes, with a potential direct industrial applicability.

Three procedures are developed and investigated for the simple and fast determination of peroxide value of olive oil by luminol chemiluminescence. The procedure using hemin as catalyst in carbonate alkaline solution allows the determination of hydrogen peroxide within the range 0.014–50 μM. The method can be used for the determination of peroxide value within the range 2.00–30.0 mequiv. O 2 /kg oil and results correlate very well ( r 2 = 0.99) with those of the official method. All reagents are aqueous solutions and olive oil is dissolved in acetone:ethanol mixed solution and, hence, the method is using minimal amounts of organic solvents and can be successfully applied to field analysis. Antioxidant activity of five common compounds found in natural products was determined by using luminol CL with Co(II) as EDTA complex as catalyst at pH 9.00.

To assess the capacity of small molecules to function as antioxidants in pathologic conditions, a set of yeast assays utilizing strains deficient in the antioxidant machinery was applied with measurements of reactive oxygen species (ROS), glutathione (GSH/GSSG), and induction of the stress responsive proteins oye2 and oye3. Yeast strains deficient in superoxide dismutase (Delta sod1), catalase A (Delta cta1), and double-deficient in Old Yellow enzyme 2 and glutathione reductase 1 (Delta oye2 glr1) were supplemented with ascorbic acid, beta-carotene, caffeic acid, or quercetin, subjected to pro-oxidant insult, and monitored for growth recovery. Ascorbic acid and caffeic acid protected cells under most circumstances, whereas beta-carotene and quercetin protection was highly context dependent, exhibiting protection in some cases and inhibition in others. Beta-carotene and quercetin elevated substantially endogenous levels of ROS in some yeast mutants. Quercetin supplementation increased significantly GSH and GSSG levels but could not maintain GSH levels in H(2)O(2)-exposed cells. Induction of the stress response machinery was manifested by the strong up-regulation of a chromosomally encoded OYE2-GFP fusion. In the case of quercetin, there was simultaneous induction of OYE3-GFP, which was previously shown to sensitize cells to H(2)O(2)-induced programmed cell death (PCD). Taken together, the results show that mutations in the antioxidant machinery affect significantly the capacity of dietary antioxidants to protect cells.

Food processing by-products and wastes represent in many instances major polluting agents, since they bear a significant load of organic bio-molecules and particularly high chemical and biological oxygen demand (COD and BOD) levels. In this regard the development of processes that will aim at reducing the polluting load by removing added-value phytochemicals from agriculture-food wastes becomes imminent. In the present study, a first approach regarding the efficient recovery of bioactive flavonols from onion solid wastes has been attempted. Major flavonols were identified by liquid chromatography-mass spectrometry techniques and recovery was achieved by using environmentally friendly and food-compatible solvent systems, composed of water/ethanol, and acidified with either acetic or citric acid and HCl. Initial screening of various mixtures showed that significantly higher recoveries (P

The aim of this study is to enrich edible oils with carotenoids and lycopene from tomato puree or tomato peel, an industrial tomato waste. These tomato derivatives were incorporated in refined olive oil, extra virgin olive oil and refined sunflower oil. The incorporation of peel enhanced the concentration of β-carotene and lycopene more than tomato puree. Furthermore, the incorporation of both tomato puree and peel induced better thermal stability of the refined olive oil compared to extra virgin oil and sunflower oil. A decrease on total phenols as well as some prooxidant activity account for this, when tomato puree was incorporated. In our oil preparations, rutin and naringenin, as flavonoids coming exclusively from tomato puree or peel, were detected. The enrichment of oils with tomato carotenoids and lycopene, in particular low quality oils like refined olive oils, might be an alternative approach to elaborate new functional foods.

1. IntroductionModernbiocatalysisaimsat the development of novel,precisetools in the view of improving a wide range of processes, whichreduce energy and raw material consumption, and generate lesswaste and toxic side-products. Although putatively useful asbiocatalysts, the principal drawbacks hindering a broaderapplicability of enzymes are the high production cost and thelow yields obtained[1]. In recent years, the use of enzymes hasgained a wider acceptance, because of the recognition thatenzymes from various plant and microbial sources have severaladvantages over conventional physical and chemical treatmentprocesses. These advantages include selective removal of parti-cular pollutants, application to xenobiotic recalcitrant com-pounds, high reaction rates, operation over a wide range of pHand salinity, reduction in sludge volume, and simplicity ofcontrolling the process[2,3].Amongthe enzymicprocesses for waste treatment, peroxidase-and phenol oxidase-catalysed treatments of phenols and aromaticamines are probably the most comprehensively studied[4,5].Bacterial mono- and dioxygenases, reductases, dehalogenases,cytochrome P450, lignin- and manganese-peroxidases have beenemployed in a spectrum of bioremediation investigations[1,5].Peroxidases (peroxidase EC 1.11.1.7) are widely distributed innature. Most peroxidases are heme proteins and contain iron(III)protoporphyrin IX (ferriprotoporphyrin IX), as the prostheticgroup. The family of peroxidases comprises yeast cytochromecperoxidase, plant ascorbate peroxidases, fungal peroxidases andother classical plant peroxidases.Peroxidases catalyse the oxidation of a wide variety ofsubstrates, using H

A very large amount of phenol-polluted waters are formed from the production of olive oil (olive mill waste water, OMWW), and the main problem associated with their disposal is a viable means of effective treatment. Biochemical processes used for treating OMWW are generally considered to be of high capital and operating costs with limited efficiency. This is mainly due to particularly high levels of phenolic compounds, which are considered major contributors to the toxicity and antibacterial activity of OMWW, and limit their microbial treatment and/or use as fertilizers. Although the use of bacterial and fungal enzymes has gained interest in studies pertaining to bioremediation applications, plant enzymes have been given less attention or even disregarded. In this view, this study aimed at investigating the use of a crude peroxidase preparation from onion solid by-products for oxidising hydrocaffeic acid, a typical o-diphenol with a structure very similar to various phenolic derivatives that may occur in OMWW. Increased enzyme activity was observed at a pH value of 4, but considerable activity was also retained for pH upto 7. Favourable temperatures for increased activity varied between 30 and 50 °C, 40 °C being the optimal. Liquid chromatography–mass spectrometry analysis of a homogenate/H2O2-treated hydrocaffeic acid solution revealed the existence of three major oxidation products, which were identified as dehydrodimers. Based on the data generated, a putative pathway for the formation of the peroxidase-mediated hydrocaffeic dehydrodimers was proposed.

The aim of this study was the detailed qualitative and quantitative analysis of the phenolic content of several extracts and fractions of Sorbus domestica fruits. The analysis was realized by LC–DAD–MS (ESI+). Twenty-four different extracts and fractions of five different maturity stages of the fruit were analyzed for comparison reasons in order to determine the most beneficial for health type of consuming. Sixty-two different phenolics were identified. There were significant qualitative and quantitative differentiations in the phenolic content among the different types of the fruits. All categories were rich in benzoic, phenylpropanoic and cinnamoylquinic acids and derivatives. Unripe fruit categories were also rich in flavonoids, while well matured fruit categories had a low content of flavonoids. Fruit pulp, which was proved to be a strong antioxidant according to previous research work, contained very low amounts of both acids and flavonoids, but its phenolic content was highly qualitatively differentiated from the other categories.

Onion solid wastes, composed of the apical trimmings and the outer dry layers of the bulb, were used as raw material for the recovery of antioxidant phenolics by employing acidified water/ethanol-based solvent systems. The extraction efficiency was assessed by measuring the reducing power and the antiradical activity of the extracts, and the total polyphenol yield. Improvement of the extraction yield was based on modifying the solvent composition and the operating conditions (temperature, time). Initial screening of various mixtures showed that significantly higher recoveries (P < 0.001) can be attained by using 60% ethanol containing 0.1% HCl. The assessment of factors affecting yield, including extraction time and temperature, was accomplished using a series of extractions on the basis of a 2 × 3 factorial design model, with time and temperature values varying from 0.5 to 6 h and from 40 to 60°C, respectively. The results obtained showed that improvement of yield is dependent upon increasing extraction time up to 6 hours, whereas increasing the temperature from 40 to 60°C had a negative effect.

A hydroalcoholic medium at pH 3.5, containing Fe 3+ and pyruvic acid, was used as the model matrix to study quercetin/catechin interactions and their possible influence on the antioxidant characteristics of the system. Incubation at 55 � C for a period of 20 days resulted in a complete disappearance of quercetin and a decrease of catechin concentration by almost 75%. Liquid chromatography–mass spectrometry analysis showed that the degradation products are mainly quercetin derivatives, but evidence also indicated that there may be the formation of a co-pigment-like, decarboxylated pyruvic acid-bridged quercetin/catechin adduct. The hydroxyl free radical scavenging activity (SAHFR) exhibited significant negative correlation (P < 0.05) with both quercetin and catechin concentration whereas the antiradical activity (AAR) was positively and significantly (P < 0.05) linked only with quercetin, stressing its importance as natural antioxidant agent with a key role in food systems. � 2007 Elsevier Ltd. All rights reserved.

The stem extract, which was shown to contain high amounts of phenolics and significant antioxidant potency, was further analysed employing liquid chromatography-electrospray ionisation mass spectrometry, in an effort to obtain a deeper insight into its polyphenolic composition. The compounds identified were mainly flavanols (a trimer and a galloylated dimer), flavonols (rutin and quercetin 3-O-glucuronide), stilbenes (trans-resveratrol and a resveratrol dehydrodimer) and a dihydroflavonol glycoside (astilbin).

Quercetin was oxidized with potassium ferricyanide under alkaline conditions, a reaction that has been previously shown to generate the same set of products deriving from oxidation by mushroom polyphenol oxidase (PPO) and horseradish peroxidase (POD). The major oxidation product was isolated and characterized by means of 1H NMR and LC–MS, and it was found to be a quercetin heterodimer [1,3,11a-trihydroxy-9-(3,5,7-trihydroxy-4H-1-benzopyran-4-on-2-yl)-5a-(3,4-dihydroxyphenyl)-5,6,11-hexahydro-5,6,11-trioxanapthacene-12-one], occurring in onion skins. Its in vitro antioxidant properties were evaluated in comparison with the parent molecule and other natural polyphenols, employing three representative tests and the alterations in the activity observed were discussed on the basis of structure–activity relationships. Biomimetic chemical oxidations of natural polyphenols may help understand oxidation pathways in plant food commodities and evaluate the consequences on their nutritional value.

The aim of this study was to investigate the carotenoid composition and the provitamin A value of three palm date (Phoenix dactylifera) varieties (Deglet-Nour, Hamraya and Tantebouchte) from Algeria at three different ripening stages (khallal, rutab and tamr). Chromatographic analysis showed that the major carotenoid pigment present in dates is lutein followed by b-carotene, with an evident carotenoid disappearance during ripening from the khallal to the tamr stage. The different date fruits present a total carotenoid content in the range of 61.7–167, 32.6–672, and 37.3–773 lg/100 g fresh weight (FW) in Deglet-nour, Tantebouchte and Hamraya varieties, respectively. The rutab stage of Tantebouchte showed the lowest carotenoid content of 32.6 lg/100 g FW, whereas the khallal stage of Hamraya presented the highest value, 773 lg/100 g FW, followed by Tantebouchte with 672 lg/100 g FW. Provitamin A value (due exclusively to b-carotene) increased from 0.4 to 0.5 RE/100 g in Deglet-Nour fruits, but decreased from 11.7 to 1.6 RE/100 g and from 3.9 to 0.5 RE/100 g in Tantebouchte and Hamraya fruits, respectively, during ripening. The lowest value was found at the tamr stage of the Deglet-Nour variety (0.5 RE/100 g) whereas the highest provitamin A content was found at the khallal stage of the Tantebouchte variety (11.7 RE/100 g).

In the present work, thirteen algae from the Aegean Sea were examined for radical-scavenging activity (RSA) using the DPPH and chemiluminescence (CL) tests. Extracts of the brown alga Taonia atomaria exhibited the best RSA in comparison to the extracts of the other investigated species and approached the activity of powerful antioxidant standards. Column chromatography separation of T. atomaria extract, followed by preparative HPLC, resulted in the isolation of six metabolites, which were identified by spectral analyses (1H NMR, 13C NMR and MS). The isolated metabolites taondiol, isoepitaondiol, stypodiol, stypoldione, sargaquinone and sargaol were found to possess marked RSA.

Flavonols are one of the most studied classes of polyphenolic phytochemicals, because of the importance pertaining to their antioxidant potency and other biological activities. Grapes and grape products such as wine constitute an integral part of the human diet, and during the past few years several studies have generated analytical data on the flavonol profile, as well as on the factors that may affect it. To further aid epidemiological research, which is based on composition tables, this review aims at providing an up-to-date compilation of data on the flavonol composition of grapes and some of the principal commodities deriving from them, including grape juices and wines. Information regarding environmental and technological parameters that may influence flavonols in these products is also reported.

The aim of the study was to evaluate the antioxidant efficacy of extracts obtained from six Pinus species (P. pinea, P. brutia, P. radiata, P. halepensis, P. attenuata, P. nigra) growing in natural forests in Southern Greece. Specimens of fresh, dry needles and pine bark were extracted and fractionated with a variety of organic solvents and the efficient concentration and their radical scavenging activity was evaluated by the Co(II)/EDTA induced luminol plateau chemiluminescence assay.

Thirty four different extracts, fractions and residues of five different maturity stages of the Greek Service tree fruits ( Sorbus domestica , fam. Rosaceae) were evaluated for their antioxidant activities (DPPH and luminol-induced chemiluminescence methods) and in correlation with their total phenolic contents (Folin–Ciocalteau test). Dichloromethane, diethyl ether and ethyl acetate fractions possessed significant radical-scavenging activities which were greater than the activity of trolox. This seemed to be correlated with their total phenolic content. Unripe yellow fruits, together with the fruit pulp, were the strongest antioxidants, while the well-matured brown fruits were the weakest ones. Results showed that the fractions of diethyl ether, ethyl acetate and dichloromethane, can be used as antioxidants in food and medicinal preparations.

The browning capacity of white wines was studied, employing an accelerated test and samples produced and stored under identical conditions. Browning was approached from a kinetic point of view and efforts were focussed on the investigation of plausible correlations with major redox-active polyphenols, including substances with an o -diphenol feature, such as gallic acid, caftaric acid, 2- S -glutathionylcaftaric acid (GRP), caffeic acid, catechin, and epicatechin. Over a period of ten days, browning development was shown to obey zero-order kinetics from the third day of the treatment, and browning rate constants ( k ) varied from 15.3 to 74.5 × 10 −3 day −1 . Regression analysis between k values and concentration of individual phenolics provided strong evidence that epicatechin is the principal browning agent ( r 2 = 0.8033, P P R ), throughout treatments, indicated that increases in browning are accompanied by a commensurate decline in the reducing ability, raising concerns about the impact of browning reactions on the in vitro antioxidant properties of white wines.

Caffeic acid (3,4-dihydroxycinnamic acid) was oxidized in wine-like model solutions (citrate buffer, pH 3.5) containing l -cysteine, by means of sodium periodate that mimics the mechanism of polyphenol oxidase (PPO). The reaction lead to the formation of a l -cysteine/caffeic acid adduct, which was isolated and tentatively identified as 2-S-cysteinylcaffeic acid (2-CCA), on the basis of LC-MS and 1H NMR data. The antioxidant properties of 2-CCA were assessed by employing the DPPH and a ferric-reducing test, and compared with both caffeic acid and l -cysteine, but also with gallic acid, which was used as a reference antioxidant. The results indicated that the adduct exhibits slightly improved antiradical activity in relation with the parent molecule (caffeic acid), but its reducing capacity was dramatically reduced, a fact that was theoretically ascribed to its strong chelating ability.

Summarization: A sensitive and simple procedure is described for determining the total phenolic/antioxidant levels of olive oil mill wastewater (OMW), using for the first time Co(II)/ethylenediaminetetracetic acid (EDTA)-induced luminol chemiluminescence. Olive oil wastewater samples were tested for their composition in simple phenolic compounds as a function of the extraction system (two- and three-phase centrifugation systems). The results revealed that the three-phase system had a stronger antioxidant activity and a higher total phenolic content than the twophase system. The relationship between antioxidant values and total phenolic content is also discussed. D 2004 Elsevier Ltd. All rights reserved. Παρουσιάστηκε στο: Environment international

The aim of this study was to determine the phenolic profile of seven different varieties of ripe date palm fruit (Phoenix dactylifera) from Algeria by LC–DAD–MS (ESI+), to investigate their respective antioxidant activities by the DPPH· method and to estimate their phenolic content using the Folin–Ciocalteu method. The total phenolic content was in the range of 2.49 ± 0.01 to 8.36 ± 0.60 mg gallic acid equivalents (GAE) per 100 g fresh fruit. This fruit was shown to possess an antioxidant activity, giving values of antiradical efficient (AE) from 0.08 ± 0.00 to 0.22 ± 0.00. The phenolic contents and the antiradical efficiencies of the different varieties were highly correlated (R2=0.975). All the varieties were found to contain mainly p-coumaric, ferulic and sinapic acids and some cinnamic acid derivatives. Three different isomers of 5-o-caffeoylshikimic acid were detected. Different types of flavonoids were identified, mainly flavones, flavanones and flavonol glycosides.