Effect of Fermentation, Cold Storage and Carbonation on the Antioxidant Activity of Probiotic Grape Beverage

Background: Grape juice is a rich source of nutritive compounds, antioxidants and phenolic compounds and could be a potential substrate for the production of probiotic grape juice. In this study, the effect of probiotic incorporation, fermentation and carbonation on antioxidant activity in grape beverage was determined. Methods: The pasteurized persi (commercial concentrated grape juice) was inoculated with three species of lactic acid bacteria (L. plantarum, L. rhamnosus and L. casei). The samples were subjected to non-fermented and fermented conditions and CO2 was injected into all aseptic bottles. Antioxidant activity and total phenol content were measured during the storage time by DPPH and Folin-Ciocalteu method, respectively. Results: The results obtained showed that the presence of probiotic and fermentation caused an increase in antioxidant activity and phenol content however; carbonation had no significant effect on the antioxidant activity of the product. Probiotic bacteria degrade tannins and can produce compounds with high free hydroxyl groups which lead to an increase in the total phenol content and antioxidant activity. CO2 can not hydrolyze large phenol contents to the small ones and therefore increase the antioxidant activity. Conclusion: Fermented probiotic grape beverage is a safe product with high antioxidant activity.