Grape polyphenols supplementation for exercise-induced oxidative stress

Exercise induces free radicals’ overproduction and therefore, an enhancement of oxidative stress, defined as an imbalance between the production of reactive species and the intrinsic antioxidant defense. Redox activity of reactive species plays an important and a positive role on exercise adaptation, but these species at very high concentrations have detrimental effects. As a result, the use of antioxidant supplements for reducing oxidative stress can be an effective health strategy to maintain an optimal antioxidant status. In this sense, grapes are an important source of natural antioxidants due to their high content in polyphenols. They have shown antioxidant potential benefits for the reduction of intense exercise effect in athletes of different sport disciplines. Consequently, it is plausible to hypothesize that a strategic supplementation with grape based products may be a good approach to mitigate the exercise induced oxidative stress. The goal of this review is to present the state of the art of supplementation effects with grape beverages and grape extracts on the oxidative stress markers in athletes. The data of polyphenolic dosages, participant characteristics and exercise protocols are reported

Grape Polyphenols Supplementation for Exercise-Induced Oxidative Stress

Exercise induces free radicals' overproduction and therefore, an enhancement of oxidative stress, defined as an imbalance between the production of reactive species and the intrinsic antioxidant defense. Redox activity of reactive species plays an important and a positive role on exercise adaptation, but these species at very high concentrations have detrimental effects. As a result, the use of antioxidant supplements for reducing oxidative stress can be an effective health strategy to maintain an optimal antioxidant status. In this sense, grapes are an important source of natural antioxidants due to their high content in polyphenols. They have shown antioxidant potential benefits for the reduction of intense exercise effect in athletes of different sport disciplines. Consequently, it is plausible to hypothesize that a strategic supplementation with grape based products may be a good approach to mitigate the exercise induced oxidative stress. The goal of this review is to present the state of the art of supplementation effects with grape beverages and grape extracts on the oxidative stress markers in athletes. The data of polyphenolic dosages, participant characteristics and exercise protocols are reported

Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity

Every year great amounts of high-quality wine grapes are left on the vine unpicked, and consequently lost, to control the overproduction in wine areas with limited appellation production yield. In the context of circular bioeconomy, the valorization of these grapes as a potential source of natural antioxidants is of great interest. The study carried out is focused on the polyphenolic profile characterization of different unpicked grape varieties using the ultrasound-assisted extraction technique to extract the polyphenolic fractions. Moreover, the evaluation of the antioxidant capacity by several assays was carried out: oxygen radical absorbance capacity (ORAC), stability of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing antioxidant capacity (FRAP), cupric reducing antioxidant capacity (CUPRAC) and stability of 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS) assays. The results showed a strong relationship between total phenolic content and hydroxycinnamic acids (R2 = 0.9088) followed by flavan-3-ols (R2 = 0.8792) and tannins (R2 = 0.7705). The antioxidant capacity of the grapes was dependent on the total phenolic content. These results supply new information for a better understanding of the importance of giving an added value to the unpicked grapes due to their high content of polyphenols. These findings help the wine sector to consider the valorization of the unpicked grapes, classified as wastes, as an interesting source of natural antioxidants to be used as food supplements and with potential applications in the pharmaceutical industry.This research received no external funding

Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity

Every year great amounts of high-quality wine grapes are left on the vine unpicked, and consequently lost, to control the overproduction in wine areas with limited appellation production yield. In the context of circular bioeconomy, the valorization of these grapes as a potential source of natural antioxidants is of great interest. The study carried out is focused on the polyphenolic profile characterization of different unpicked grape varieties using the ultrasound-assisted extraction technique to extract the polyphenolic fractions. Moreover, the evaluation of the antioxidant capacity by several assays was carried out: oxygen radical absorbance capacity (ORAC), stability of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing antioxidant capacity (FRAP), cupric reducing antioxidant capacity (CUPRAC) and stability of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS) assays. The results showed a strong relationship between total phenolic content and hydroxycinnamic acids (R2 = 0.9088) followed by flavan-3-ols (R2 = 0.8792) and tannins (R2 = 0.7705). The antioxidant capacity of the grapes was dependent on the total phenolic content. These results supply new information for a better understanding of the importance of giving an added value to the unpicked grapes due to their high content of polyphenols. These findings help the wine sector to consider the valorization of the unpicked grapes, classified as wastes, as an interesting source of natural antioxidants to be used as food supplements and with potential applications in the pharmaceutical industry

Fast Electrochemical Measurement of Laccase Activity for Monitoring Grapes’ Infection with Botrytis cinerea

Grapes’ infection with the fungi Botrytis cinerea is one of the major causes of economic loss in the winemaking sector worldwide. The laccase activity of grapes is considered an appropriate indicator of this type of fungal infection, and enzymatic activity higher than 3 U/mL indicates a high risk of irreversibly damaged grape must due to enzymatic browning. This work describes a fast test for the measurement of laccase activity based on a dual optical and electrochemical detection method. A paper sensor impregnated with the enzymatic substrate dye 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) provides a semi-quantitative optical measurement. While the paper sensor can be used independently, when combined with a screen-printed electrode and amperometry measurements, it enables the quantitative detection of laccase activities down to 0.4 U/mL in only 5 min. The method was applied for monitoring the artificial infection of white, rosé, and red grapes with different strains of Botrytis cinerea. The results were confirmed by parallel analysis using the spectrophotometric method of laccase activity determination based on syringaldazine. The influence of the fungal strain and type of grape on laccase activity levels is reported. The demonstrated robustness, simplicity, and versatility of the developed method make it ideal for application on-site in the vineyard or at grape processing points.Financial support provided by the Romanian Executive Agency for Higher Education, Research, Development and Innovation (UEFISCDI), ERANET-MANUNET-III-WINBIOTOOL-2, contract 151/9.03.2020 grant (for A.V), contract150/9.03.2020 (for P.E) and contract 152/9.03.2020 (for C.P. (Catalina Pantazi), E.B., and M.I.); the Romanian Academy grant RO1567-IBB05/2021 (for R.R. and C.P. (Cristina Purcarea)); the Basque Government and the European Union through the European regional development fund 2014–2020 (FEDER) (ZL-2020/00532 and ZL-2021/00340); and the Diputación Foral de Álava (ALAVA INNOVA program—INNOEM-2020/00045) for Bodegas de los Herederos del Marqués de Riscal; and the Diputación Foral de Álava (ALAVA INNOVA program— INNOEM-2020/00045) for Bodegas de los Herederos del Marqués de Risca is gratefully acknowledged

Extracción y caracterización de antocianos y procianidinas de distintas variedades de uva empleadas en la elaboración del txakoli tinto de Bizkaia

En el presente trabajo se ha realizado la extracción y el posterior estudio cromatográfico y espectroscópico de compuestos antociánicos y procianidinas en uvas tintas de variedades autóctonas empleadas en la elaboración del Txakoli de Bizkaia, y en uvas de variedad foránea. La extracción se llevó a cabo tanto sobre el hollejo como sobre las pepitas del fruto, mediante aplicación de diversas técnicas. La posterior determinación se efectuó poniendo a punto un método cromatográfico que permitió el aislamiento de los compuestos antociánicos extraídos. Tanto el análisis como la posterior identificación de los compuestos en base a sus propiedades espectrales se realizó empleando la técnica acoplada HPLC-PD

Aplicación de métodos espectroscópicos al estudio de las características cromáticas de los componentes polifenólicos presentes en vinos

El presente trabajo de investigación tiene como objetivo la determinación de los compuestos polifenólicos más representativos presentes en el Txakoli de Bizkaia, así como el estudio y su relación con las características cromáticas. La determinación de estos compuestos polifenólicos, se ha realizado mediante el empleo de técnicas espectroscópicas, llevándose a cabo el análisis en muestras de Txakoli Blanco, Rosado y Tinto de diversas variedades. Además, se ha efectuado una comparación de las metodologías aplicadas, contrastando los resultados obtenidos. Así mismo, se ha llevado a cabo un estudio sobre la influencia de las distintas variedades en los parámetros cromáticos y valores triestimulare

Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity

Every year great amounts of high-quality wine grapes are left on the vine unpicked, and consequently lost, to control the overproduction in wine areas with limited appellation production yield. In the context of circular bioeconomy, the valorization of these grapes as a potential source of natural antioxidants is of great interest. The study carried out is focused on the polyphenolic profile characterization of different unpicked grape varieties using the ultrasound-assisted extraction technique to extract the polyphenolic fractions. Moreover, the evaluation of the antioxidant capacity by several assays was carried out: oxygen radical absorbance capacity (ORAC), stability of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing antioxidant capacity (FRAP), cupric reducing antioxidant capacity (CUPRAC) and stability of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS) assays. The results showed a strong relationship between total phenolic content and hydroxycinnamic acids (R2 = 0.9088) followed by flavan-3-ols (R2 = 0.8792) and tannins (R2 = 0.7705). The antioxidant capacity of the grapes was dependent on the total phenolic content. These results supply new information for a better understanding of the importance of giving an added value to the unpicked grapes due to their high content of polyphenols. These findings help the wine sector to consider the valorization of the unpicked grapes, classified as wastes, as an interesting source of natural antioxidants to be used as food supplements and with potential applications in the pharmaceutical industry