Green Acerola (Malpighia emarginata) Extraction Optimization, Cellular Antioxidant Activity, and Spray Drying: Toward a Stable Vitamin C-Rich Powder.

Abstract

Green acerola (Malpighia emarginata) is among the richest natural sources of vitamin C and represents a promising raw material for natural antioxidant food ingredients. Extraction of ascorbic acid from whole green acerola fruits was optimized using response surface methodology, with solvent composition and temperature as independent variables. Pure water at 35 °C provided the highest ascorbic acid recovery (340 mg g⁻¹ dry material) and reducing power, alongside strong antioxidant activity by ABTS and DPPH assays. The biological relevance of the optimized extract was evaluated using Saccharomyces cerevisiae wild-type and erg6Δ mutant strains as a cellular antioxidant model under menadione-induced oxidative stress. In the presence of the extract (500 mg L⁻¹), cell viability was maintained for up to 5 h in the wild-type strain and 3 h in the erg6Δ mutant, compared to approximately 1 h in untreated controls. The extract was subsequently stabilized by spray drying with arabic gum as carrier, yielding a powder with water activity of 0.213 and no significant loss of antioxidant composition or activity. These results establish mild aqueous extraction combined with spray drying as an effective strategy for producing a stable, vitamin C-rich green acerola powder with demonstrated cellular antioxidant activity, suitable for food ingredient applications.