Enhancement of Antioxidant Activity in a Fermented Grape Juice Using Selected Oenococcus oeni Strains
Luciana Del Valle Rivero, Carmen Maturano, Maria Jose Rodriguez-Vaquero,* and Fabiana Maria Saguir
*CONICET – UNT, Ayacucho 471, 4000, Argentina (firstname.lastname@example.org)
Fermented beverages, such as grape wines and fruit juice are associated with human health benefits due to the presence of high concentrations of phenolic compounds. In winemaking, the lactic acid bacterium Oenoccocus oeni performs malolactic fermentation (FML), a process that deacidifies wine by decarboxylating L-malic acid, contributes to microbial stability, and modifies the aroma profile and sensory impacts. This study investigated changes in the composition of sugars, organic acids, and phenolic compounds in a fermented grape juice by O. oeni strains in relation to antioxidant activity. O. oeni MS46 and MS9 were inoculated into juice prepared from Malbec grapes from the Cafayate region and bacterial growth, glucose, citric acid, malic acid consumption, and acetic and lactic acids production were evaluated. O. oeni MS46 was inoculated into wine elaborated by alcoholic fermentation to lead FML and the phenolic compounds content and antioxidant activity were determined and compared with commercial wines. In grape juice, both strains grew in 12 days, 5 to 10% of the glucose was consumed, and L-malic and citric acids were completely consumed. The consumption of glucose and citrate were accompanied by production of D-lactic acid and acetic acid; the molar yield indicated that acetic acid was mainly formed from citrate. O. oeni MS46 had the highest malolactic potential. Wine elaborated by O. oeni MS46 had the most antioxidant activity and this activity was related to the phenolic compound content. We selected O. oeni MS46, whose metabolic properties were tested in a natural environment and in wine for potential biotechnological application.
Funding Support: PICT 2015-1508 Prestamo Bid CIUNT – PIP-CONICET