Adaptation of two groups of Oenococcus oeni strains to red and white wines: the role of acidity and phenolic compounds.

AIMS: Oenococcus oeni is the lactic acid bacteria species which is the most adapted to wine. Recently, two groups of strains that form two genetic lineages were described in red and white Burgundy wines. The aim of this study was to analyse the phenotypes of these strains in order to determine how they have adapted specifically to either red or white wine. METHODS AND RESULTS: Four strains from each group were tested in grape must and in wines to evaluate their tolerance to pH and to phenolic compound content. White wine strains proved to be the most tolerant to low pH, both in grape must and in wine, whereas they were inhibited by the presence of grape tannins in wine. Red wine strains were more sensitive to acidity, but very resistant to phenolic compounds. CONCLUSIONS: The results suggest that pH and phenolic compounds drive strain selection at several stages of wine production. SIGNIFICANCE AND IMPACT OF THE STUDY: Although it is well known that O. oeni is well adapted to wine, this study shows that strains of some genetic lineages within this species have evolved to adapt better than others to specific types of wines.

Use of oak wood during malolactic fermentation and ageing: Impact on chardonnay wine character.

Malolactic fermentation (MLF) and oak barrels aging are two oenological processes which modify wine composition and sensory characteristics. The effect of MLF-container (stainless steel tanks, barrels) and barrel toasting (T1, T2, T3) on ellagitannin concentration, volatile composition and sensory attributes of Chardonnay wines was evaluated. Barrel toasting had higher impact on ellagitannin content than MLF-container. When comparing both MLF-modalities, barrel-fermented wines exhibited greater amounts of vanillin and whiskey-lactones but lower concentrations of fruity aroma compounds. Regarding sensory analysis, greater citrus and floral aromas were perceived for MLF-tank wines, and higher nuts aroma for MLF-barrel wines. Using barrels as MLF-containers i) did not change the aroma perception defining Chardonnay character (peach, apricot and gun flint); ii) did not impact the aromatic intensity and persistence, sweetness, acidity, mouthfeel volume and/or bitterness; and iii) did not confer significantly higher overall woody aromas which might mask fruity, floral and mineral (gun flint) character.

Chemical and sensorial investigation of in-mouth sensory properties of grape anthocyanins.

Anthocyanins are water-soluble pigments found in the cell vacuoles of fruits and flowers, performing several roles from insects attraction to stress protection. Their antioxidant activity contributes to human health, and consuming plant-derived products provides their higher source in the diet. Although their colour and nutritional features, their contribution to sensory properties of foods has not been widely investigated. In wine, preferences are connected with sensory attributes of colour, aroma, taste, and mouthfeel. In this study, grape anthocyanin extracts (TAE) were fractionated using centrifugal partition chromatography (CPC) and preparative HPLC in three fractions, i.e glucoside (GF), acetylated (AF) and cinnamoylated (CF) anthocyanins. Sensory properties were investigated by chemical analysis, as reactivity towards bovin serum albumin (BSA) and salivary proteins, and in tasting sessions to assess anthocyanins best estimated thresholds (BET) in wine-like solution. Anthocyanins reacted with both BSA and salivary proteins, but to different extents, because higher interaction between salivary proteins and anthocyanins were found. Cinnamoylated anthocyanins are the most reactive to salivary proteins. Tasting sessions suggested an involvement of anthocyanins as in-mouth contributors in wine, since their BETs were 255, 297, 68, and 58 mg/L for TAE, GF, AF, and CF, respectively, and the descriptors reported were astringency and bitterness.

Ellagitannin content, volatile composition and sensory profile of wines from different countries matured in oak barrels subjected to different toasting methods.

Ellagitannins and aromatic compounds evolution in Cabernet Sauvignon wines macerated in oak barrels for a year was studied. Identical barrels with different toastings (medium toasting, medium toasting with watering, Noisette) were used in French, Italian and USA cellars. Ellagitannins increased by 84-96% with aging time, as did woody volatiles, by 86-91% in French wines and 23-35% in Italian wines, while fruity aroma compounds declined by 50-57% in the French and Italian wines over a 12-months period. Nevertheless, other behaviors and different kinetics rates for these compounds were observed depending on barrel toasting, wine matrix and their interactions. Perceived overall woody intensity was closely related to trans-whiskey lactone, guaiacol and vanillin, whereas astringency and bitterness were significantly linked to ellagitannins (p<0.05). This is the first study that evaluates the toasting effect on wines from different countries matured in the same oak barrels.

Delayed tumor onset in transgenic mice fed an amino acid-based diet supplemented with red wine solids.

Increased consumption of vegetable foods (cereals, legumes, fruits) and some beverages (tea, cider, wine) is associated with reduced risk of cancer. Polyphenols in these foods and beverages are thought to be responsible, based on data from in vitro assays and from in vivo studies that used animals pretreated with carcinogen and given tea or polyphenol-spiked water to drink. We tested the hypothesis that dehydrated-dealcoholized red wine (wine solids), when consumed as part of a precisely defined complete diet, would delay tumor onset in transgenic mice that spontaneously develop externally visible tumors without carcinogen pretreatment. Sibling transgenic mice were weaned onto an amino acid-based diet alone or supplemented with red wine solids. Mice were examined daily; the age at which a first tumor appeared was recorded as the age of tumor onset. The concentration of the major polyphenol of red wine (catechin) in blood serum was also measured at the end of the study. The supplemented diet was fed continuously for three generations to ensure that it supported normal growth and reproduction. We discovered that the wine solid supplement delayed tumor onset, that intact catechin was absorbed, and that the supplemented diet supported normal growth and reproduction for three generations. Also, our simple experimental protocol offers an alternate and/or complementary way to identify foods, beverages, and their constituents that delay tumor onset and to investigate possible mechanisms involved.

High-performance liquid chromatography coupled with fluorescence detection for the determination of trans-astringin in wine.

In this study a high-performance liquid chromatography (HPLC) method was developed for the determination of trans-astringin in wine using fluorescence detection. This is the first time the occurrence of trans-astringin has been reported in wine. The method allows analysis of both red and white wine samples with no prior treatment. The quantification threshold is 0.03 mg/l. Levels of trans-astringin in the French wines analyzed ranged from 0.09 mg/l to 0.29 mg/l. The reproducibility of the method was measured and the CV was less than 4.8% for both red and white wines.

Vanadium pharmacokinetics and oral bioavailability upon single-dose administration of vanadyl sulfate to rats.

Vanadium pharmacokinetic parameters and oral bioavailability were determined after administration of vanadyl sulfate, an antidiabetic agent, to male Wistar rats. An optimal sampling design was used over a 21-day period; vanadium was measured in blood by atomic absorption spectrophotometry (AAS). After i.v. bolus injection (3.025 mg V/kg body weight), a three-compartment model was fitted to the data. Mean (+/- SD) half-lives were 0.90 +/- 0.56 hours, 24.8 +/- 14.5 h and 201 +/- 74 h, respectively, for the three phases observed. Vanadium clearance averaged 37.6 +/- 15.8 mL/h. Initial volume of distribution was 2.43 +/- 1.22 L/kg whereas total volume of distribution was 25.4 +/- 3.9 L/kg; these values largely exceeded body weight (i.e. 300 g), in agreement with a great uptake and retention of vanadium in tissues. After oral gavage administration (15.12 and 7.56 mg V/kg body weight), vanadium disposition was best described by a three-compartment model, with absorption appearing to occur by a zero-order rate. This process lasted 10.3 +/- 1.3 h and 10.9 +/- 1.1 h for the two dosage levels, respectively. Half-lives corresponding to the terminal log-linear part of the curve were 173.5 +/- 1.6 h and 172 +/- 6 h (Bayesian estimates). No dose-dependency was observed for any of the parameters determined. Absolute bioavailabilities, with reference to the i.v. administration, were 12.5% and 16.8% when determined from AUCmod. Bioavailability appeared to be higher than generally stated in the literature.

Inhibition of oxidation of human low-density lipoproteins by phenolic substances in different essential oils varieties.

Phenolics antioxidant phytochemicals have been recently implicated for the lower rates of cardiac disease mortality among people consuming a Mediterranean diet. Essential oils are natural products extracted from vegetable materials, which can be used as antibacterial, antifungal, antioxidants, and anti-carcinogenic agents or to preserve and give specific flavors to foods. The activities of 23 selected essential oils in inhibiting the copper-catalyzed oxidation of human-low-density lipoproteins (LDL) were determined in vitro. LDL oxidation was inhibited between 6, 2, and 83% by 2 microM (GAE) total phenolics. The relative inhibition of LDL oxidation was used to categorize the essential oils into four groups below 2% when they contained methylchavicol, anethol, p-cymen, apiole, cinnamic ether; 6-10% if they possessed a majority of carvacrol, thymol, p-cymene, or vanillin; 10-50% for moderate amounts of thymol, carvacrol, cuminol, or eugenol; and 50-100% when eugenol is the major component. Total phenol content of essential oils gave a correlation with LDL antioxidant activity of r = 0.75. The Activity of each phenolics compound could play a role in protecting LDL against oxidation if the substance is absorbed by the body.

Levels of flavan-3-ols in French wines.

French wines are abundant sources of phenolic compounds. The content of several catechins, i.e., (+)-catechin, (-)-epicatechin, dimers B1, B2, B3, and B4, trimers C1, and trimer 2 (T2), of 160 French wines was determined by HPLC with UV detection. Red wines (n = 95) were found to have high levels of catechins, ranging from 32.8 to 209.8 mg/L (mean concentration 114.5 mg/L) for (+)-catechin, from 22.1 to 130.7 mg/L (mean concentration 75.7 mg/L) for (-)-epicatechin, from 7.8 to 39.1 mg/L (mean concentration 25.4 mg/L) for B1, from 18.3 to 93 mg/L (mean concentration 47.4 mg/L) for B2, from 21.4 to 215.6 mg/L (mean concentration 119.6 mg/L) for B3, from 20.2 to 107.2 mg/L (mean concentration 81.9 mg/l) for B4, from 8.6 to 36.9 mg/L (mean concentration 26.3 mg/L) for C1, and from 26.7 to 79.3 mg/L (mean concentration 67.1 mg/L) for T2. White and rosé wines (n = 57 and n = 8) were found to have low levels of (+)-catechin (mean concentrations 9.8 and 10.6 mg/L, respectively) and (-)-epicatechin (mean concentrations 5.3 and 6.5 mg/L, respectively). These data provide a basis for the epidemiological evaluation of catechin intake by the consumption of French wine.

Antioxidant capacities and phenolics levels of French wines from different varieties and vintages.

Phenolics from grapes and wines can play a role against oxidation and development of atherosclerosis. Levels of phenolics, major catechins [(+)-catechin, (-)-epicatechin, procyanidin dimers B1, B2, B3, and B4], phenolic acids (gallic acid and caffeic acid), caftaric acid, malvidin-3-glucoside, peonidin-3-glucoside, and cyanidin-3-glucoside were quantified by HPLC with UV detection for 54 French varietal commercial wines taken from southern France to study the antioxidant capacity and the daily dietary intake of these compounds for the French population. The highest antioxidant capacity was obtained with red wines and ranged from 12.8 mmol/L (Grenache) to 25.2 mmol/L (Pinot Noir). For white wines, Chardonnay enriched in phenolics by special wine-making was found to have an antioxidant capacity of 13.8 mmol/L, comparable to red wine values. For red wines classified by vintages (1996-1999) antioxidant capacities were approximately 20 mmol/L and then decreased to 13.4 mmol/L for vintages 1995-1991. Sweet white wines have 1.7 times more antioxidant capacity (3.2 mmol/L) than dry white wines (1.91 mmol/L). On the basis of a still significant French wine consumption of 180 mL/day/person, the current daily intake of catechins (monomers and dimers B1, B2, B3, and B4) averaged 5 (dry white wine), 4.36 (sweet white wines), 7.70 (rosé wines), 31.98 (red wines), and 66.94 (dry white wine enriched in phenolic) mg/day/resident for the French population. Red wine, and particularly Pinot Noir, Egiodola, Syrah, Cabernet Sauvignon, and Merlot varieties, or Chardonnay enriched in phenolics during wine-making for white varieties contribute to a very significant catechin dietary intake.

Determination of stilbenes (trans-astringin, cis- and trans-piceid, and cis- and trans-resveratrol) in Portuguese wines.

Stilbenes have been shown to have cancer chemopreventive activity and to protect lipoproteins from oxidative damage. A method is described for their direct determination in different types of wine using high-performance liquid chromatography with ultraviolet detection. In a survey of 120 commercial wines from Portugal and France, the highest concentrations of stilbenes were found in red wines. The glucosides of resveratrol were present in higher concentrations than the free isomers. Isolation from wine and characterization of trans-astringin in a large quantity are described for the first time.

Determination of platinum in wine by graphite furnace atomic absorption spectrometry.

A method based on graphite furnace atomic absorption spectrometry (GFAAS) was developed for determining platinum in wine. Wine samples were prepared by microwave acid digestion or dry mineralization. The method of standard addition was used for Pt determination in untreated wine samples and mineralized samples. Analyte modifiers and furnace conditions were optimized. Effects of cations (Mg2+, Ca2+, K+, Na+, and NH4+) and anions (PO4(3)-, SO4(2)-) were tested separately and in combination. Analytical characteristics of the method were optimized for analyte recovery and signal enhancement. Recoveries ranged from 92.5 to 102%, and precision reproducibility relative standard deviation varied from 7.5 to 10%. Red, rosé, and white wines from France were analyzed. Platinum levels found in most wines were very low (< 10 micrograms/L).

Speciation analysis of organolead compounds in wine by capillary gas chromatography/microwave-induced-plasma atomic emission spectrometry.

A method was developed for the speciation analysis of ionic organolead compounds in wine. The analytes were extracted as diethyldithiocarbamate complexes into hexane and propylated with a Grignard reagent. The derivatized extract was analyzed by capillary gas chromatography/microwave-induced-plasma atomic emission spectrometry. The method of standard additions was used for calibration to correct for variable recoveries and signal enhancements. Red, rosé, and white wines from southern France were analyzed. Trimethyllead was the ubiquitous species. The wines made from grapes grown close to industrial zones showed elevated concentrations of ethyllead species. The concentrations of methyllead and ethyllead found in wines were compared with the concentrations of organolead found in rain water and plant sap collected in the viticultural regions. The ratio of methyllead to ethyllead in wines greatly exceeded the same ratio found in atmospheric deposits.

A preliminary characterization of Aglianico (Vitis vinifera L. cv.) grape proanthocyanidins and evaluation of their reactivity towards salivary proteins.

The flavan-3-ol and proanthocyanidin composition of Aglianico seeds and skins were for the first time determined by HPLC-MS in comparison with the international grapes Merlot and Cabernet Sauvignon. Monomers [(+)-catechin C, (-)-epicatechin EC, (-)-epicatechin-3-O-gallate, ECG] and oligomers [B1, B2, B3, B4 dimers and trimer C1] were identified and quantified in grape extracts. In order to evaluate the reactivity towards salivary proteins of model wine solutions of seeds and skins monomeric/oligomeric and polymeric fractions, the Saliva Precipitation Index (SPI) was carried out. Fractions were also analyzed for their mean degree of polymerization (mDP), percentage of galloylation (%G) and of prodelphinidin (%P) by phloroglucinolysis. Aglianico was the most effective in precipitating proteins than Merlot and Cabernet Sauvignon, mainly for the high percentage of galloylation of grape fractions. The mDP and the percentage of ECG in terminal units resulted to significantly contribute to the precipitation of salivary proteins by grape proanthocyanidins.

Kinetics of browning, phenolics, and 5-hydroxymethylfurfural in commercial sparkling wines.

We analyzed the degree of browning (absorbance at 420 nm), the phenolics, and the 5-hydroxymethylfurfural (5-HMF) content in six sparkling wines series kept at three temperatures (4, 16, and 20 °C) for over 2 years. Caffeic acid, trans-coutaric acid, p-coumaric acid, and 5-HMF were the compounds with the greatest correlation with browning and time. 5-HMF was the only compound that evolved linearly at all temperatures. We propose that 5-HMF is a better time-temperature marker than the A420 parameter or phenolics, because it shows higher linearity with time at all temperatures, is more sensitive to temperature changes, and has lower variability. The kinetics of 5-HMF was studied showing a zero-order behavior. We propose mathematical models that wineries can use to predict the browning shelf life of their sparkling wines as a function of the storage time and temperature.

Characterization of seed and skin polyphenolic extracts of two red grape cultivars grown in Croatia and their sensory perception in a wine model medium.

A study of proanthocyanidin and anthocyanin composition and concentrations in seed and skin extracts of two Croatian native red grape cultivars (Plavac mali and Babic) by HPLC-UV-Fluo/MS analysis was conducted in this work. A sensory analysis of extracts astringency and bitterness intensity was also performed. In the seeds, Babic showed generally higher concentrations of proanthocyanidins, while in the skins, Plavac mali showed higher concentrations of proanthocyanidins and anthocyanins. Babic proanthocyanidin seed fractions, greater in polymer size and percentage of galloylation, were perceived to be significantly more astringent. Babic proanthocyanidin skin fractions, greater in polymer size and lower in percentage of galloylation and prodelphinidins, were perceived to be significantly bitterer, but only in polymeric fractions. A positive correlation was found between the degree of polymerization, the percentage of galloylation and astringency intensity in the seeds. A negative correlation was found between the percentage of prodelphinidins and bitterness intensity in the skins.

Comparison of (+)-catechin determination in human plasma by high-performance liquid chromatography with two types of detection: fluorescence and ultraviolet.

In this study we developed a high-performance liquid chromatography (HPLC) method for the determination of (+)-catechin in human plasma, using both fluorescence and UV detection. Sample preparation involved precipitation of plasma proteins using acetonitrile, followed by direct injection into the HPLC system using both types of detection. Validation of accuracy and precision were satisfactory for both within- and between-batch assays. For fluorescence detection, coefficients of variation were less than 6.47% and mean relative errors were within +/-4.8%. The average recovery was 85.31%. The limit of detection and quantification were 5 ng/ml and 40 ng/ml, respectively. Ultraviolet detection was also used but appeared less sensitive and selective than fluorescence detection. This new method provides a simple, accurate, precise and specific method for the determination for (+)-catechin in plasma.

Vanadium levels in French and Californian wines: influence on vanadium dietary intake.

An accurate and reproducible method for direct determination of vanadium (V) in wine using graphite furnace atomic absorption spectrometry (GFAAS) is described. This method gave results insignificantly different from those obtained using dry mineralization of wine samples, with a detection limit of 42 pg. A total of 68 wine samples from different regions of France and California were analysed. Vanadium levels ranged from 7.0 to 90.0 micrograms/l in red and from 6.6 to 43.9 micrograms/l in white wines. The method was also adapted to the determination of vanadium levels in 12 grape samples from different varieties after acid mineralization. Vanadium content varied from 2 to 17 micrograms/kg for white and from 5 to 11 micrograms/kg for red varieties. Our data indicate that wine storage conditions may increase vanadium content. The contribution of wine consumption to daily vanadium dietary intake of the French population was estimated to be 11 micrograms/day per individual.