Phenolic Compound Modification by Oenococcus oeni Increases Antioxidant Activities in Apple Wine
Irina Kristof, Silvana Cecilia Ledesma, Gisselle
Raquel Apud, Nancy Roxana Vera and Pedro Adrián Aredes
Fernández*
*Universidad Nacional de Tucumán, Ayacucho 471, San Miguel de
Tucumán, Tucumán, Argentina, 4000, Argentina
(pedro.aredes@fbqf.unt.edu.ar)
The antioxidant properties of apple wine (AW) can produce benefits to human health and are mainly attributed to phenolic compound (PC) content. The metabolism of Oenococcus oeni can modify the phenolic profile during malolactic fermentation (MLF) fermentation, and consequently, its antioxidant activity. Pasteurized apple juice was fermented with Saccharomyces cerevisiae EC1118 to obtain AW. Then, MLF was performed separately with two autochthonous RAM10 and RAM11 strains of O. oeni and a commercial VP41 strain. A control without MLF was carried out. The MLF was performed at 18°C for five days. High-performance liquid chromatography was used to monitor changes in concentration of 17 PCs during MLF, using a reversed-phase Kinetex C18 column coupled with a DAD-FLD detector. Antioxidant activity was determined using the FRAP method, and radical scavenging activities were determined by DDPH and ABTS. Caffeic acid was the major compound, representing more than 90% of the PCs analyzed, and its concentration increased after MLF. Myricetin, (-)-epicatechin, and phloretin were detected only after MLF and p-coumaric acid was only detected in the sample obtained from the RAM11 strain. DPPH radical scavenging activity remained unchanged, but increases in ABTS and FRAP activities were observed after MLF. The greatest antioxidant activity was obtained using the VP41 strain, which produced an increase of >60 and 15% in the ABTS and FRAP activities, respectively, over AW without bacterial inoculation. The RAM10 and RAM11 strains did not show significant differences in antioxidant activity after MLF. Controlled MLF with appropriate indigenous or commercial O. oeni strains increases antioxidant activities by PC modification.
Funding Support: Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
