Aim: To clarify the effects of selenium (Se), parameters related to oxidative issues, as well as the antioxidant response were investigated on an autochthonous wine yeast strain. Methods and Results: Antioxidant enzyme activity, gel electrophoresis, Western blot and MDA level were used to investigate the effects of different concentration of Se in wine yeast. We found that Se is able to affect the enzymatic activities of catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD). An increase in lipid peroxidation was observed in a dose-dependent manner of (Se), thus, indicating the occurrence of cell membrane damage. Additionally, Se induced post-translational oxidative modifications of proteins, especially oxidation of thiol groups (both reversible and irreversible) and protein carbonylation (irreversible oxidation). Conclusion: These results obtained could further the understanding the effect of different concentration of Se in wine yeast strain with which Se affect the enzymatic activities and induces some post-translational modifications of proteins. Significance and Impact of the Study: The understanding of mechanisms regulating the response of wine yeast to Se is important for future work using selenized yeast as enriched Se supplements in human nutrition.

During technological processing, proanthocyanidins and anthocyanidins could be partly lost due to the complexation phenomena, affecting food and beverage nutritional properties, organoleptic properties and health-promoting potentials. A common issue is encountered when processing food and beverage which is binding of phenolics to dietary proteins. The present investigation aims at evaluating the proteolysis contribution, using pure protease (Pepsin, 3000 units g À1 ), to protein-anthocyanidin and protein-proanthocyanidin interactions. Bovine serum albumin (BSA), ovalbumin (OVA) and casein (CAS) dietary protein models were used. High-performance liquid chromatography coupled to diode array detector (HPLC-DAD) and size exclusion chromatography analyses proved that pepsin treatment significantly (P > 0.05) decreased the ratio of flavonoids' interaction with tested proteins . The proteolysis reduced anthocyanidin interactions with CAS, OVA and BSA by 64.88%, 57.37% and 42.87% respectively. Similarly, proanthocyanidins interaction with CAS, OVA and BSA were reduced by 34.23%, 13.74% and 2.39% respectively. This study provides the basis to develop innovative technologies to limit protein-flavonoid complexation during food and beverage processing.

No abstract