Nanoencapsulation of synergistic combinations of acai berry concentrate to improve antioxidant stability.

The objectives of this study were to increase the antioxidant activity of acai berry concentrate (Acai) by combining it with various antioxidants to exploit synergistic effects and improve antioxidant stability by nanoencapsulation. Ascorbic acid and trolox were identified as synergistic antioxidants for Acai. The optimal mixing ratio of ascorbic acid (74.64 μg/mL) and trolox (47.88 μg/mL) for synergistic activity in both oxygen radical absorbance capacity (ORAC) and DPPH assays was 1.56:1. A mixture of Acai, ascorbic acid, and trolox at the optimum ratio was nanoencapsulated using chitosan and gum arabic. Nanoparticles exhibited homogenous dispersion with a 230 to 260 nm particle size. During storage, nanoparticles exhibited better antioxidant stability than non-nanoencapsulated antioxidants. These results suggest that mixing Acai with ascorbic acid and trolox or nanoencapsulating this mixture with chitosan and gum arabic are both effective techniques for improving antioxidant activities.