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Polyphenols in red wine are bioactive compounds with positive effects on health and disease prevention. White grape musts and wines have a lower concentration of phenolic compounds compared to the red ones and are therefore considered less beneficial to health. In Andalucia, a region located in the South West of Spain, Pedro Ximenez white grapes are desiccated under the sun for a week before they are pressed and the juice (must) is obtained. This ancient procedure increases the variety and content of polyphenols present in the Pedro Ximenez must (PXM). We incorporated PXM into the daily diet of aged Mus spretus mice (24 months) and investigated their properties by comparing several parameters determined in these old mice with those measured in young mice (two months old). Biochemical, histological, and transcriptional analyses indicated that PXM exhibited potent antioxidant properties, promoted the normalization of the biotransforming ability of several cytochromes, i.e., the P450 family, in the liver, and regularized hepatic apoptosis, promoting proliferation instead. Our data indicated that PXM possesses a profound ability to promote liver regeneration in terms of both the structure and the function, thus contributing to a healthy aging process.

Production of sparkling wines involve a second alcoholic fermentation and contact with yeast less over an extended period of time, which influences the aroma composition and sensory quality of the resulting wines. Sparkling wines obtained with two yeast strains inoculated as free cells, immobilized in alginate bed and bioimmobilized as biocapsules, were aged during 32 months. Among the volatile compounds, high Odor Activity Values were obtained with isoamyl acetate, ethyl propanoate, ethyl butanoate, ethyl 3-methylbutanoate, ethyl hexanoate, ethyl octanoate, hexanol, 2-methoxy-4-vinylphenol, decanal, octanoic acid, decanoic acid and TDN. Taken together these contribute more than 70% of the overall aromatic series value. Although some results rely more on the yeast strain than the inoculation format, specific aroma compounds were associated with the immobilization format, allowing the classification of sparkling wines by PCA. As a result the aroma quality of sparkling wines could be improved using immobilized yeasts. info:eu-repo/semantics/acceptedVersion

Mesoporous nanomaterials were used to prevent protein haze in Muscat Ottonel and Pedro Ximénez wines. Major volatile compounds, polyols and turbidity were analyzed in fined wines and the results were compared with untreated and fined with bentonite wines. Two commercial mesoporous nanomaterial labelled as SBA-15 and MCM-41 provided a notable turbidity reduction and prevent protein haze as was demonstrated by the heat stability tests. Only, the siliceous material labelled as KIT-6 was not suitable for wine fining. All the chemical families were affected by the fining agents, although the loss of aroma compounds was lower with nanomaterials than with bentonite. The impact on volatile compounds concentration depends on tested wine, independently on the fining agent used. Wines were distinguished by principal components analysis, which was carried out using the volatile compounds as classifying variables. Wines treated with SBA-15 were closest to the control wine in terms of volatile compounds concentration.

Volatile aroma compounds of Feteasca neagra wines, aged for 1.5 and 3 months in oak barrels with different toast degree, have been analyzed using stir bars sorptive extraction and gas chromatography coupled to mass spectrometry. Principal components analysis of the volatile aroma permits wine differentiation according to the toast degree of the barrels used and also according to aging time. Wine fingerprints were obtained using the aromatic series. Cluster analysis showed that the differences among wines due to the toast degree of the barrels become progressively larger with aging time. Regarding phenolic families, flavonols and flavanols increased with aging time, whereas polymeric compounds decreased due to the precipitation phenomenon. The wines aged in light toast barrels were those with the higher phenolic concentration. The toast degree and the aging time influence significantly the aroma and phenolic composition of the aged wines. Sensory analysis indicated that wines aged for 3 months show the best valuation, highlighting those aged in barrels with medium toast degree. All these changes must be taken into account by the winemaker in order to produce wine with the best quality.

Aged mice consumed water supplemented with Pedro Ximenez must (PXM). After 20 weeks, histological analyses showed that PXM consumption highly alleviated the age-related hepatic damage observed in control mice, restoring the cytoplasmic appearance and normal arrangement of hepatic cords of young mice. Bidimensional electrophoresis of 5-IAF labeled hepatic proteins showed changes in the reversibly oxidized thiol status of 42 protein spots. Fourteen proteins were identified. Seven (FAM210B, RPE, SRSF1, KRT1, ATF1, ZEB1, IgM) resulted reduced and other seven (RPL29, GABPB1, ACTB, DDC, INA, PRKAR1B, ZFP738) oxidized. For 6 proteins (ATF1, RPE, ZEB1, IGM, PRKAR1B and ZFP738) the susceptibility of a particular Cys to reversible oxidation was analyze. The histological changes, the variations in the oxidation status of protein thiolic groups and the identification of specific Cys residues affected, indicated that the PXM must is acting as an antioxidant but also a pro-oxidant that might help the elderly liver to regenerate.

Aging is characterized by deterioration of biomolecules and impaired stress responses that make the elderly especially vulnerable to environmental pollutants. The pesticide p,p'-DDE is a DDT derivative that generates great concern because of its wide distribution and its harmful effects on both human health and the environment. We analyzed here the biological responses elicited by p,p'-DDE exposure in the liver of aged Mus spretus mice. Data demonstrate that the elderly constitute a population especially sensitive to this noxious environmental pollutant. We also demonstrated here that the daily consumption of sun-dried Pedro Ximenez (PX) white-grape must (PXM) protects the liver of aged mice from both the age and the damages caused by p,p'-DDE exposure. The PXM activity was exerted through the restoration of the hepatic metabolisms of lipids and carbohydrates and, probably, is a consequence of the ability of this polyphenol-rich mixture to avoid oxidative stress. Nutritional interventions including PXM, which ameliorates the effects of unavoidable exposure to pesticides in our food, are helpful tools that can help elderly populations to enjoy a healthy and expanded lifetime.

Sunlight exposure is a traditional way to dry postharvested white Pedro Ximenez grapes, and the dried grapes are the basis of a sweet fortified wine elaborated in the South of Spain. In this paper, we have studied the effect of seven days of exposure of grapes to sunlight. The phenolic content in the skins and flesh has been determined. The transient induction of phenolics has been detected and identified in skins by HPLC and MS/MS. Maximum induction was after 2 days exposure with an increase in the levels of quercetin-3-O-glucoside, engeletin (dihydrokaempferol-3-O-rhamnoside) and astilbin (taxifolin 3-O-rhamnoside). We have evaluated the antioxidant and protective effects of the phenolic extracts of these grapes in Saccharomyces cerevisiae after exposure to H2O2. Phenolic extracts reduced the basal intracellular level of peroxides in a concentration dependent manner. There was a corresponding significant reduction in carbonylated proteins in treated and control cells and increased survival of yeast cells exposed to H2O2. Our results indicate that sundried grapes display a high antioxidant capacity resulting in a decrease in the oxidative cellular environment.

The use of Saccharomyces cerevisiae to produce sweet wine is difficult because yeast is affected by a hyperosmotic stress due to the high sugar concentrations in the fermenting must. One possible alternative could be the coimmobilization of the osmotolerant yeast strains S. cerevisiae X4 and X5 on Penicillium chrysogenum strain H3 (GRAS) for the partial fermentation of raisin musts. This immobilized has been, namely, as yeast biocapsules. Traditional sweet wine (that is, without fermentation of the must) and must partially fermented by free yeast cells were also used for comparison. Partially fermented sweet wines showed higher concentration of the volatile compounds than traditionally produced wines. The wines obtained by immobilized yeast cells reached minor concentrations of major alcohols than wines by free cells. The consumption of specific nitrogen compounds was dependent on yeast strain and the cellular immobilization. A principal component analysis shows that the compounds related to the response to osmotic stress (glycerol, acetaldehyde, acetoin, and butanediol) clearly differentiate the wines obtained with free yeasts but not the wines obtained with immobilized yeasts.

Pedro Ximenez grapes were sun dried for 0, 2, 4, 6 and 9 days and the resulting must was analysed by gas chromatography and by an electronic nose. In the last stages of the process compounds related with ripe fruity and toasty aromas decreased whereas the concentration of sugars increases slightly, which suggests that the optimum dehydration time is reached before the ninth day. A discriminant analysis of data by the electronic nose allows for the differentiation of the must from dried grapes. Multiple regression analysis was made with the aim of relating the aroma that best described the must from dried grapes with the data reported by the electronic nose, obtaining a correlation above 99%. Therefore, according to the obtained results the electronic nose can be used as a tool for quick analysis that can help winemakers to decide the optimum drying time, taking into account the concentration of volatile compounds.