Antioxidant activity evaluation of the fungal dye oil-in-water emulsions obtained by cyclic voltammetric technique

Antioxidant potential of the fungal dye, produced by a strain selected from the collection of Epicoccum nigrum bioresearch platform (acronym MIUG) was partially characterized in previous studies. However, the fungal dye antioxidant capacity compared with other potential colorant inhibitors of lipid peroxidation (e.g. cochineal dye) has not been fully elucidated, especially regarding its behavior in emulsions. In the present study, by a voltammetric technique, the antioxidant potential of yellow dye synthesized by fermentation in SSF system Epicoccum nigrum strain selected MIUG 2.15, after immobilization by emulsification in model food emulsions was evaluated. Fungal dye antioxidant activity in stable emulsions is correlated to its electrochemical behavior. Thus, to highlight the potential of oxidation of emulsions containing dyes the cyclic voltamograms (scan rate: 100 mVs) were determined. Corresponding oxidation peaks were observed more clearly, compared with the corresponding reduction, which were lower. Regarding the control emulsion, which relate to the antioxidant effect of dyes present in the system is properly noted the appearance of a little platinum electrode; the equilibrium potential is E0 = -835 mV. From cyclic voltamograma peak of the emulsion with propyil gallate is notes the reduction in peak intensity for platinum electrode and the appearance of an anode peak (-589.3 mV), corresponding to the propyil gallate introduced in emulsion. Specifically in the case of emulsion containing the cochineal or fungal dye is the appearance of two second anode and cathode peaks in cyclic voltamogram, which means that in this case, there were several redox processes induced by this dyes in emulsions. On the other hand, the currents are small to very small. This is due to-OH groups and = C = a specific colour, which are largely responsible for its antioxidant activity. For fungal dye emulsion the cyclical voltamogram have less defined redox processes. However, small peaks can be assigned to oxidation conjugated double bonds systems present in flavonoids which are found in fungal dye, perhaps by producing a radical intermediate during the oxidation process.