A review of the content of the putative chemopreventive phytoalexin resveratrol in red wine

Resveratrol, a naturally occurring compound of various fruits such as grapes, is thought to possess chemopreventive properties. The levels of resveratrol in grapes and grape products including wine, varies from region to region and from one year to another. This paper reviews the resveratrol content in red wine based on relevant published data. Red wine contains an average of 1.9 ± 1.7 mg trans-resveratrol/l (8.2 ± 7.5 μM), ranging from non-detectable levels to 14.3 mg/l (62.7 μM) trans-resveratrol. In general, wines made from grapes of the Pinot Noir and St. Laurent varieties showed the highest level of trans-resveratrol. No region can be said to produce wines with significantly higher level of trans-resveratrol than all other regions. Levels of cis-resveratrol follow the same trend as trans-resveratrol. The average level of trans-resveratrol-glucoside (trans-piceid) in a red wine may be as much as 29.2 mg/l (128.1 μM), i.e., three times that of trans-resveratrol.     

Determination of flavan-3-ols and trans-resveratrol in grapes and wine using HPLC with fluorescence detection

Concentrations of trans-resveratrol, catechin and epicatechin were analyzed in musts and wines produced from seven red and four white grape cultivars from various wine growing regions of Turkey. Phenolics were quantified using an HPLC method optimized for the separation of wine phenolics. Wine samples contained higher phenolics levels than the corresponding musts. With the exception of Semillion, white wines and musts contained lower concentrations of phenolics than red wines and musts. However, the white cultivar Semillion had the highest concentrations of catechin and epicatechin among all wine and must samples. Semillion wine catechin and epicatechin were 13.7 and 11.8 mg/L, respectively. The highest level of trans-resveratrol among the white cultivars was found in Narince wine (1.93 mg/L). Within the red wine and must cultivars, Bo?azkere, Öküzgozü, and Cabernet contained the highest concentrations of flavan-3-ols and trans-resveratrol. Catechin was the major phenolic in all wines and most musts. Epicatechin was the major phenolic in 6 of the 11 must samples, but none of the wine samples. trans-Resveratrol was generally found in lowest concentrations in both wines and musts.     

Stilbene levels and antioxidant activity of Vranec and Merlot wines from Macedonia: Effect of variety and enological practices

The content of the stilbenes trans-resveratrol and piceid as well as the antioxidant activity of Macedonian red wines from the two main grape varieties Vranec and Merlot have been evaluated. Тhe effects of time of maceration, type of yeast and the level of sulphur dioxide applied on stilbene content and antioxidant activity have been studied. The most important factor in winemaking technology is the maceration time since the highest concentrations of trans-resveratrol, piceid and highest antioxidant activity were found following 6 and 10 days of maceration. Concerning the yeast type, higher concentrations of trans-resveratrol and piceid have been obtained with French yeast “Levuline CHP” in comparison to Macedonian yeast “Vinalco”. In contrast, the higher antioxidant activity of wines from both varieties of grapes was observed by application of Macedonian yeast “Vinalco”.     

Determination of trans-resveratrol in red wine by adsorptive stripping square-wave voltammetry with medium exchange

In the present paper, a method for the determination of trans-resveratrol in red wine samples, by adsorptive stripping square-wave voltammetry (Ad-SSWV) in a glassy carbon electrode, is presented. In 0.10 M perchloric medium, trans-resveratrol experiments an adsorptive–oxidative process, which promotes the appearance of a peak at 0.72 V. Calibration graph have been constructed from 5.0 to 35 ng/mL. Detection limit of 4.2 ng/mL has been calculated, according to Clayton criterion. Extraction of trans-resveratrol from red wine with diethylether and posterior clean-up with C18 cartridges is carried out. Recovery percentages close to 100% have been calculated with different red wine samples. The accumulation of analyte in the electrode is carried out at +0.60 V for 60 s, in the presence of 0.10 M HClO₄ and 10% of ethanol; the measurement stage is performed after a medium exchange, in 0.10 M HClO₄ and 30% of ethanol. The standard addition method was employed for the analysis of real samples, since a matrix effect is observed in red wine extract. The method has been applied to several commercial red wines samples, and the results have been satisfactorily validated by HPLC.     

Antioxidant capacity and stilbene contents of wines produced in the Snake River Valley of Idaho

Forty-two wines produced from grapes grown in Idaho were examined in this study. The samples examined were from four monovarietal wines (12 Cabernet Sauvignon, 9 Merlot, 7 Riesling, 14 Chardonnay). Wine samples represented twelve wineries that obtain their fruit from vineyards located within Idaho’s Snake River Valley. Titratable acidity, pH, specific gravity, colour measurements (lightness, chroma, and hue), % haze, total anthocyanins, total phenolics, total tannins, antioxidant capacity, and individual stilbene measurements were performed. The antioxidant capacities (ORAC values) of Idaho wines ranged from 3.1 (Merlot wine) to 87.0 (Cabernet Sauvignon wine) μmol of Trolox/ml (mean = 38.5 μmol of Trolox/ml). Mean ORAC values of Merlot wines (mean = 27.6 μmol of Trolox/ml) were lower than the other three styles (mean for Cabernet Sauvignon wines = 41.0 μmol of Trolox/ml, mean for Chardonnay wines = 42.8 μmol of Trolox/ml, and mean for Riesling wines = 39.4 μmol of Trolox/ml). Free stilbene levels (four different stilbenes) were examined by direct-HPLC/DAD/ESI-MS/MS method. Piceid and resveratrol (both trans- and cis-) were found in the samples. Stilbene levels ranged from 0.97 (Riesling wine) to 12.88 (Cabernet Sauvignon wine) mg (expressed as trans-resveratrol)/l. This is the first paper to report the current chemical composition of Idaho wines.     

Rapid,simple and sensitive determination of the apparent formation constants of trans-resveratrol complexes with natural cyclodextrins in aqueous medium using HPLC

The study of the complexation of trans-resveratrol with natural cyclodextrins (CDs) in aqueous medium under different physico-chemical conditions of pH or temperature is essential if this antioxidant compound is to be used successfully in the food industry as ingredient of functional foods, due its poor stability, bioavailability and solubility. In this paper, a rapid, simple and sensitive determination of the apparent formation constant of trans-resveratrol/CD complexes by HPLC in aqueous medium has been investigated for first time. It can be observed that trans-resveratrol forms a 1:1 complex with α-, β- and γ-CD. The highest value of the apparent formation constant (K_F = 1922 ± 89 M⁻¹) was found for β-CD and a strong dependence of K_F on pH can be seen in the region where the trans-resveratrol begins the deprotonation of their hydroxyl groups. Moreover, an increase in the system’s temperature produced a decrease in the values of K_F. Finally, to gain information on the mechanism of the trans-resveratrol affinity for CD, the thermodynamic parameters of the complexation were obtained.     

Chocolate and cocoa: New sources of trans-resveratrol and trans-piceid

trans-Resveratrol and trans-piceid were found for the first time in dark chocolate (at least 0.4 ppm trans-resveratrol and 1 ppm trans-piceid) and cocoa liquor (at least 0.5 ppm trans-resveratrol and 1.2 ppm trans-piceid). Because these compounds are highly sensitive to light, a specific extraction procedure was required to recover them, involving delipidation with toluene and cyclohexane and ethanol/water (80/20, v/v) solid–liquid extraction at 60 °C before reverse-phase HPLC-MS/MS analysis (atmospheric pressure chemical ionization [APCI] in the positive mode). Thanks to an exceptionally high procyanidin content, chocolate products displayed higher antioxidant activity than much more concentrated commercial stilbene extracts.     

Phenolic profile,antioxidants, and sensory acceptance of bioactive-enhanced peanuts using ultrasound and UV

Phenolic antioxidant compounds, including resveratrol, are associated with reduced risk of cancer and cardiovascular disease, and delayed ageing. This study aims to quantify synergistic enhancement of phenolics and antioxidants in peanuts by combinations of ultrasound (US)–UV treatments, compared to either US or UV, and determine optimum parameters for combined US–UV process. LC–MS confirmed the bioactive phenolics: trans-resveratrol, trans-piceid, and p-coumaric-, caffeic-, and ferulic-acids, which achieved maximum increases, with combined US–UV, compared to US or UV; as did total phenolics (TP), TEAC, and ORAC. Optimum parameters for a combined US–UV process will provide up to 4.8 μg/g trans-resveratrol, 170 μg/g p-coumaric acid, and 150 μM TE/g ORAC or >100% that found in red wines; 1.0 μg/g trans-piceid, 2.6 μg/g ferulic acid, 1.48 mg GAE/g TP, and consumer acceptance ?5. Optimum combined US–UV resulted in 1.3× or 2.3× the trans-resveratrol concentrations in US or UV, respectively, suggesting synergistic effect of UV and US in enhancing resveratrol in peanuts.     

Uptake and utilization of trans octadecenoic acids in lactating dairy cows

Trans fatty acids (FA) arise in ruminant-derived foods as a consequence of rumen biohydrogenation and are of interest because of their biological effects and potential role in chronic human diseases. Our objective was to compare 2 trans FA, elaidic acid (EA; trans-9 18:1) and vaccenic acid (VA; trans-11 18:1), with oleic acid (OA; cis-9 18:1) relative to plasma lipid transport and mammary utilization for milk fat synthesis. Three ruminally cannulated, Holstein dairy cows, 259 ± 6 DIM (mean ± SEM), were randomly assigned in a 3 × 3 Latin square design. Treatments were a 4-d abomasal infusion of 1) OA (45.5 g/d), 2) EA (41.7 g/d), and 3) VA (41.4 g/d). Milk samples were collected at each milking and blood samples were collected at the start and end of each treatment period. The proportions of total plasma FA associated with each plasma lipid fraction at baseline (pretreatment) were 62.6 ± 0.6% phospholipids, 26.1 ± 0.6% cholesterol esters, 9.8 ± 0.4% triglycerides, and 1.5 ± 0.1% nonesterified fatty acids; these values were unaffected by treatment. There were striking differences in the FA composition of the individual plasma lipid fractions and in the distribution of specific 18-carbon FA among the lipid fractions. Infusion of treatment isomers caused their specific increase in the various plasma lipid fractions but had no effect on milk production variables, including milk fat yield and content. Transfer efficiency of infused OA, EA, and VA to milk fat averaged 65.5 ± 3.0%, 59.7 ± 1.5%, and 54.3 ± 0.6%, respectively. For the VA infusion, 24.6 ± 1.1% of the transfer was accounted for by the increased yield of cis-9, trans-11 conjugated linoleic acid in milk fat, consistent with its endogenous synthesis from VA via the mammary enzyme Δ⁹-desaturase. Notably, linoleic acid (18:2n-6) and linolenic acid (18:3n-3) accounted for 47.7% of total plasma FA, but only 2.6% of FA in milk. Overall, results demonstrate clear differences in plasma transport and mammary uptake and utilization of 18-carbon FA, and these relate to the location, orientation, and number of double bonds.     

Matrix effects on the bioavailability of resveratrol in humans

The pharmacokinetics of resveratrol in 11 healthy male volunteers has been assessed in a randomized, crossover, controlled clinical trial after the administration of three grape products: red wine (250 mL), grape juice (1/L), or tablets (red wine extracts enriched with trans-resveratrol). Doses of trans-resveratrol independently of the product administered, were about 14 μg/kg. Biological samples were collected and analysed by capillary gas chromatography–mass spectrometry. cis-Resveratrol, trans-resveratrol and dihydroresveratrol were determined in plasma and urine. Plasma concentration of trans-resveratrol after hydrolysis increased as a response to all grape products and that of cis-resveratrol after wine and grape juice. Free forms of these phenolic compounds were deemed undetectable in plasma. Despite similar trans-resveratrol doses being administered, its bioavailability from wine and grape juice was 6-fold higher, than that from tablets. Resveratrol was better absorbed from natural grape products than from tablets, pointing out the importance of the matrix in its bioavailability.     

Determination of resveratrol in grains,hulls and leaves of common and tartary buckwheat by HPLC with electrochemical detection at carbon paste electrode

A reverse-phase high-performance liquid chromatographic method for the determination of trans-resveratrol with spectrophotometric detection (306 nm) and amperometric detection at carbon paste electrode (E = + 1,2 V) was developed and tested on real samples of grains, hulls and leaves of six varieties of common buckwheat (Fagopyrum esculentum Möench) and two varieties of tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.). Optimal conditions for the determination of trans-resveratrol were as follows: column Kromasil C-18 (7 μm), 125 × 4 mm; mobile phase acetonitrile: diluted BR buffer pH 7 (50:50, 30:70 for grains and hulls and 20:80 for leaves); flow rate 1 ml min⁻¹. Under these conditions, the limit of detection of trans-resveratrol (L_D) was 3.5 × 10⁻⁸ mol l⁻¹ (R² = 0.9986) for electrochemical detection and 3.2 × 10⁻⁸ mol l⁻¹ (R² = 0.9993) for spectrophotometric detection.     

Growth and carcass fatty acid composition of beef steers fed soybean oil for increasing duration before slaughter

Duration of soybean oil (SBO) supplementation needed to enhance carcass conjugated linoleic acid (CLA) and trans-vaccenic (TVA) content was examined using 96 beef steers (293.6 ± 3.9 kg) fed a 78% corn-based diet supplemented with SBO for 0, 77, 137, or 189 days before slaughter. Duration of SBO supplementation had no effect (P ? 0.15) on animal performance or carcass traits, nor (P ? 0.15), total, total saturated, or total polyunsaturated fatty acids of Longissimus dorsi (LD). Concentrations of CLA in LD were not affected (P ? 0.18) by SBO supplementation. Concentrations of monounsaturated fatty acids (MUFA) decreased linearly (P = 0.03) in LD, whereas TVA increased (P = 0.04) in adipose tissue and tended (P = 0.07) to increase in LD with increasing duration of SBO supplementation. Supplementing SBO to a concentrate-based diet may enhance TVA without impacting CLA, while reducing the MUFA content of lean beef.     

Profiling of bioactive compounds in cultivars of Runner and Valencia peanut market-types using liquid chromatography/APCI mass spectrometry

Peanuts are classified into four market-types (Runners, Spanish, Virginia and Valencia). Studies on their phytochemical composition have focused mainly on market-types other than Valencia. The objectives of this study are to evaluate the phytochemical composition of cultivars of Valencia and Runner market-types. Extracts of 25 peanut cultivars of Runner and Valencia market-types were analysed using HPLC-DAD-MS analysis. Results showed major differences in UV profile of the market-types. A major peak with m/z 317 identified as isorhamnetin was present only in Valencia cultivars while its glycoside (isorhamnetin-3-O-rutinoside) having m/z 625 was identified in both market-types. Genistein, daidzein, rutin, quercetin and trans-resveratrol were also identified and quantified. Genistein and daidzein concentrations (0.03 mg/100 g) were similar in both market-types. trans-Resveratrol and rutin were significantly (p < 0.05) higher in Runner cultivars while quercetin was 10-fold higher (0.60 ± 0.04 mg/100 g) in Valencia cultivars making them a better source of this phytochemical.     

Examination of the persistency of milk fatty acid composition responses to fish oil and sunflower oil in the diet of dairy cows

Based on the potential benefits of cis-9, trans-11 conjugated linoleic acid (CLA) for human health, there is a need to develop effective strategies for enhancing milk fat CLA concentrations. Levels of cis-9, trans-11 CLA in milk can be increased by supplements of fish oil (FO) and sunflower oil (SO), but there is considerable variation in the response. Part of this variance may reflect time-dependent ruminal adaptations to high levels of lipid in the diet, which lead to alterations in the formation of specific biohydrogenation intermediates. To test this hypothesis, 16 late lactation Holstein-British Friesian cows were used in a repeated measures randomized block design to examine milk fatty acid composition responses to FO and SO in the diet over a 28-d period. Cows were allocated at random to corn silage-based rations (8 per treatment) containing 0 (control) or 45 g of oil supplement/kg of dry matter consisting (1:2; wt/wt) of FO and SO (FSO), and milk composition was determined on alternate days from d 1. Compared with the control, the FSO diet decreased mean dry matter intake (21.1 vs. 17.9 kg/d), milk fat (47.7 vs. 32.6 g/kg), and protein content (36.1 vs. 33.3 g/kg), but had no effect on milk yield (27.1 vs. 26.4 kg/d). Reductions in milk fat content relative to the FSO diet were associated with increases in milk trans-10 18:1, trans-10, cis-12 CLA, and trans-9, cis-11 CLA concentrations (r² = 0.74, 0.57, and 0.80, respectively). Compared with the control, the FSO diet reduced milk 4:0 to 18:0 and cis 18:1 content and increased trans 18:1, trans 18:2, cis-9, trans-11 CLA, 20:5 n-3, and 22:6 n-3 concentrations. The FSO diet caused a rapid elevation in milk cis-9, trans-11 CLA content, reaching a maximum of 5.37 g/100 g of fatty acids on d 5, but these increases were transient, declining to 2.35 g/100 g of fatty acids by d 15. They remained relatively constant thereafter. Even though concentrations of trans-11 18:1 followed the same pattern of temporal changes as cis-9, trans-11 CLA, the total trans 18:1 content of FSO milk was unchanged because of the concomitant increases in the concentration of other isomers (Δ^4-10 and Δ^12-15), predominantely trans-10 18:1. In conclusion, supplementing diets with FSO enhances milk fat cis-9, trans-11 CLA content, but the high level of enrichment declines because of changes in ruminal biohydrogenation that result in trans-10 replacing trans-11 as the major 18:1 biohydrogenation intermediate formed in the rumen.     

Centrifugal partition chromatography followed by HPLC for the isolation of cis-ε-viniferin,a resveratrol dimer newly extracted from a red Algerian wine

Grapes and related products are considered the major dietary sources of stilbenes. Among these compounds, trans-resveratrol is one of the most important in terms of biological activity, since it has been reported to prevent or to slow the progression of a wide variety of illnesses. We report for the first time the isolation and structure elucidation of cis-ε-viniferin, a biologically active resveratrol dihydrodimer from a red Algerian wine. The Merlot wine was fractionated by column chromatography followed by centrifugal partition chromatography (CPC) and then by reverse-phase semi-preparative HPLC. The structure of cis-ε-viniferin was elucidated by means of 1H NMR and 2D correlations. Cis-ε-viniferin concentrations were determined in wine samples originating from North Africa, most of which are commercially available in France. Stilbene quantification was based on an HPLC method with diode array detection. Unlike trans-ε-viniferin, cis-ε-viniferin was present in almost all wine samples studied and the concentrations ranged from 0.10 to 1.12 mg/l.     

Carotenoids and antioxidant capacities from Canarium odontophyllum Miq. fruit

Carotenoids were isolated and identified from peel, pulp and seed fractions of Canarium odontophyllum Miq., and their antioxidant capacities were evaluated. all-trans-β-carotene was present in a large amount in peel (69.5 ± 1.0 mg/kg), followed by pulp (31.1 ± 0.76 mg/kg) and seed (15.1 ± 3.0 mg/kg). Additionally, 15-cis-β-carotene, 9-cis-β-carotene and 13-cis-β-carotenes were also major contributors to carotenoid contents in peel, pulp and seed fractions. Pulp exhibited excellent β-carotene bleaching activity, significantly higher than peel and seed; high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, whereas peel exhibited significantly higher scavenging activity of 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals. All the extracts exhibited good inhibitory effect against hydrogen peroxide-induced haemoglobin oxidation, ranging from 45.3 to 59.7%. This is the first report about carotenoids and antioxidant capacities from C. odontophyllum fruit, and indicates that this fruit can be explored and promoted as a potential source of natural antioxidants.     

Maximising resveratrol and piceid contents in UV and ultrasound treated peanuts

The effects of varying doses of UV and ultrasound (US) treatments on the concentrations of resveratrol, piceid and total stilbenes, and sensory overall acceptance of peanuts were evaluated using response surface methodology. UV and US treatments resulted in increased (α < 0.05) resveratrol, piceid and total stilbenes but decreased overall acceptance compared to untreated controls. US produced higher concentrations of stilbenes compounds but lower overall acceptance compared to UV treatment. The optimum US process will produce 2.64–4.40 μg/g resveratrol and 4.50–6.50 μg/g total stilbenes which are more than that will be achieved by the optimum UV process with 2.00–2.06 and 2.10–2.27 μg/g, respectively. On a per serving basis, if a peanut bar contains 30 g peanuts, 3–5 bars of US- or 6 bars of UV-treated containing bars will have the same resveratrol content as a serving of 140 mL-glass of red wine.     

The formation of potentially harmful compounds in churros, a Spanish fried-dough pastry,as influenced by deep frying conditions

Colour, moisture, hydroxymethylfurfural (HMF) and acrylamide (AA) were investigated in traditional Spanish churros. Samples were deep-fried in sunflower oil at lab-scale temperatures of 180, 190 and 200 °C and for frying times of 2, 3, 5 and 7 min. Fresh made churros were also obtained from local producers. HMF ranged from 1.2 ± 0.02 to 221.4 ± 2.02 mg/kg for lab-scale experiments and an average of 74.3 ± 47.5 mg/kg was recorded in commercial samples. AA ranged from below the limit of quantitation to 90 ± 0.6 μg/kg for lab-scale experiments and an average of 46 ± 24.5 μg/kg was measured in commercial samples. Temperatures between 185 and 200 °C are commonly used to obtain churros with an acceptable palatability and a crispy surface. However, HMF and AA levels increased nearly two-fold from 190 to 200 °C at the same frying times, indicating that a more precise control of frying temperatures is required to minimize their formation.     

Effect of weaning status on lipids of Galician Blond veal: Total fatty acids and 18:1 cis and trans isomers

The effect of weaning at different ages (NW = not weaned, W5 = 5.5 months and W2 = 2 months) on fatty acids (FA) of the Longissimus thoracis (LT) muscle was studied in 36 Galician Blond (GB) calves. Total FA (TFA) were determined by gas chromatography (GC) and 18:1 isomers by a combination of reversed-phase high performance liquid chromatography (HPLC) and GC. NW group showed higher (P < 0.001) values of n-3 polyunsaturated FA (PUFA), conjugated linoleic acid (CLA) and 18:1trans-11 compared to LT from W5 and W2 calves. W2 calves showed the highest levels of n-6 PUFA (P < 0.01), 18:1trans-10 and 18:1trans-6/7/8 (P < 0.001). Generally, W5 calves had intermediate values for TFA and 18:1 isomers. As the suckling period was longer, GB milk and veal FA profiles became more similar, it seems that muscle FA were partially transmitted by the milk FA intake due to the persistence of the reticular grove closing reflex.     

cis/trans-Isomerisation of triolein,trilinolein and trilinolenin induced by heat treatment

To estimate the trans-fatty acid production of edible oils during the frying process, 1.0 g of triolein, trilinolein and trilinolenin, as representative oils, were heated at 180 °C for a defined period. The amounts of trans-fatty acids in heated triacylglycerols were quantitatively determined by gas chromatography after methylation. It was revealed that heating induced cis to trans-isomerisation of unsaturated triacylglycerols, and that trans-fatty acid amounts increased gradually, depending on the heating period. For example, trans-isomer amounts in triolein, trilinolein and trilinolenin (per gram) were 5.8 mg, 3.1 mg and 6.5 mg, respectively, after 8 h incubation at 180 °C. At that time, the contents of polar compounds contained in the heated triolein, trilinolein and trilinolenin were 22%, 27% and 31%, respectively. When triolein was heated under a N₂ stream, neither trans-isomerisation nor polar compounds were detected. The addition of α-tocopherol (1.0%) to triolein significantly prevented not only lipid oxidation but also trans-isomerisation during heating. A commercially available vegetable oil was also heated under the same conditions as these model oils. Compared with the trans-isomerisation in model oils, the degree of trans-isomerisation in the edible oil was relatively low. Tocopherols in the oil would prevent not only lipid oxidation but also isomerisation. These results suggest that the geometric isomerisation of unsaturated fatty acids during heating accompanies lipid oxidation.