No abstract

The phenolic compound profile and content of red wines are modified during the maceration-fermentation process by several factors that alter the extractability of the compounds and by reactions that phenolic compounds undergo, and can be directly related to the quality of the final wine and its beneficial effects on the consumer. The aim of this study was to determine the change in phenolic content and profile during cold pre-fermentative maceration and fermentation without the removal of grape pomace. Total phenolics, flavonoids, anthocyanins, tannins and antioxidant capacity were determined by spectrophotometric methods, and the phenolic profile was determined by HPLC-MS on each day of the maceration-fermentation process. The results showed a variation in the content of phenolic compounds and antioxidant activity over time, but the final phenolic content showed no significative difference compared with the initial content (1 268 mg GAE/L and 1 115 mg GAE/L respectively). The phenolic profile showed that flavonoids were the principal compounds in wine and that they increased at the end of the winemaking. Condensed tannins also increased during fermentation, while anthocyanins and some phenolic acids decreased at the end of the process. The final content of phenolic compounds was similar to the initial one, but there was a change in the different fractions of phenolic compounds at the end of fermentation.

Red wines and their grape pomaces are important sources of phenolic compounds. Inhibition of platelet aggregation is one of the mechanisms proposed for cardioprotective effect of phenolic compounds from wine and grape pomace; however, phenolic content is affected by region, variety and winemaking process. In the present study, antiplatelet effect of red wines and grape pomaces was related to its phenolic content (determined by spectrophotometric techniques) and profile (determined using HPLC-MS/MS). in vitro Anti-platelet aggregation was determined using human platelets. Results showed that Zinfandel wine and Cabernet Sauvignon grape pomace presented the highest phenolic content. Phenolic profiles presented differences in the presence of flavonoids and oligomeric tannins. Results from platelet aggregation showed that Merlot and Petit Verdot wines and Petit Verdot grape pomace sample presented the highest antiaggregant effect. These results indicate that antiplatelet effect could be related to phenolic profile than phenolic content in wines and grape pomaces. Cardioprotective effect of red wines and grape pomace could be related to specific compounds such as monomeric and polymeric flavan-3-ols.

Nota: Artículo recibido el 09 de enero de 2017 y aceptado el 24 de abril de 2017. ARTÍCULO ORIGINAL resumeNLa mezcla de ácidos fosfomolíbdico y fosfotúngstico es el reactivo esencial de uno de los principales métodos para la cuantificación de compuestos polifenólicos en extractos vegetales conocido como método de reactivo de Folin-Ciocalteu (FC). Sin embargo, al igual que otros métodos espectrofotométricos puede ser inespecífico e interaccionar con otras moléculas como azúcares, presentes en los extractos vegetales, que pueden alterar los resultados encontrados. El objetivo del presente trabajo fue determinar el efecto de la glucosa, sacarosa, fructosa, xilosa, manosa, ramnosa y arabinosa sobre la cuantificación de compuestos polifenólicos mediante el método de FC. La fructosa y la xilosa fueron los azúcares con la mayor reactividad, mientras que la sacarosa, ramnosa, manosa y glucosa presentaron el menor efecto. La fructosa y la manosa tanto en las muestras de ácido gálico como en extractos de anís y chile jalapeño así como de especias tradicionales de la cocina mexicana (hoja santa y hoja de aguacate), reaccionaron diferente, ya que la fructosa incrementó la respuesta del método y consecuentemente sobreestimó el contenido de los compuestos polifenólicos y la manosa los subestimó. Los resultados obtenidos muestran que el contenido de azúcar en extractos puede interferir en la estimación de los compuestos polifenólicos, sobre todo si la concentración es muy alta o la fructosa está presente.Palabras Clave: azúcares, enediol, fenoles totales, Folin-Ciocalteu. New approach to the interaction between Folin-Ciocalteu reactive and sugars during the quantification of total phenolsabstract Phosphomolybdic and phosphotungstic acids mixture, known as Folin-Ciocalteu reactive, is one of the main methods for the quantification of polyphenolic compounds in vegetable extracts (FC reactive). However, as other spectrophotometric methods, it can be unspecific and interact with other molecules, such as sugars, present in vegetable extracts, modifying the obtained results. The aim of the present study was to evaluate the effect of glucose, sucrose, fructose, xylose, mannose, rhamnose and arabinose on the quantification of polyphenolic compounds by the FC method. Fructose and xylose showed the highest interaction with FC reactive, while sucrose, mannose, rhamnose and glucose showed the lowest effect. Fructose and mannose reacted differently with both gallic acid solutions and anise, jalapeño hot pepper and traditional Mexican spices (hoja santa and avocado leaves). Fructose increased the response of the method, and consequently overestimated the polyphenolic content, while mannose showed an underestimation. The obtained results showed that sugar content in vegetable extracts may interfere on the estimation of polyphenolic content, especially if high content of fructose is present in the samples.

The beneficial health effect of red wine depends on its phenolic content and the phenolic content in red wines is affected by ecological, agricultural, and enological practices. Enriched wines have been proposed as an alternative to increase the phenolic content in wines. Nevertheless, phenolic compounds are related to the sensory characteristics of red wines, so enrichment of red wines requires a balance between phenolic content and sensory characteristics. In the present study, a Merlot red wine was enriched with a phenolic extract obtained from Cabernet Sauvignon grape pomace. Two levels of enrichment were evaluated: 4 and 8 g/L of total phenolic content (gallic acid equivalents, GAE). Wines were evaluated by a trained panel to determine their sensory profile (olfactive, visual, taste, and mouthfeel phases). The bioaccessibility of phenolic compounds from enriched red wines was evaluated using an in vitro digestive model and phenolic compounds were quantified by High Performance Liquid Chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). Enrichment increased mainly flavonols and procyanidins. Such an increase impacted astringency and sweetness perceived by judges. This study proposes an alternative to increase the phenolic content in wines without modifying other main sensory characteristics and offers a potential beneficial effect on the health of consumers.