The stabilities of the phenolic compounds, antioxidant activity and colour parameters of microencapsulated powdered BRS Violeta red grape juice were evaluated throughout storage at 5, 25 and 35°C for up to 150days. Different soy protein (S) or whey protein (W) blends with maltodextrin (M) were used as carrier agents, added at diverse concentrations and proportions. The treatment combining S and M with the highest carrier agent concentration (1SM) preserved almost all the anthocyanins. Except for 1SM, the proportion of p-coumaroylated anthocyanins increased during storage, and the flavonol content of the 1SM powder decreased after 150days. The hydroxycinnamate content decreased for all treatments, independent of storage temperature, and flavan-3-ols were lost at 35°C. The time and temperature did not influence the antioxidant activity of the powder or the colour of the reconstituted grape juice after 150days.
Keywords: Anthocyanins; Antioxidant activity; Colour; Maltodextrin; Microencapsulation; Soy protein; Stability; Whey protein.
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