Stability and antioxidant properties of freeze-concentrated acerola juice in water-in-oil-in-water emulsions

• Formation of W/O/W emulsions from freeze-concentrated acerola extract using spontaneous emulsification method. • Showing that the Tween 80 was suitable for the fabrication of W/O/W emulsion. • Demonstrating the effect of stirring speed and component proportions on W/O/W emulsion formation. Acerola, known for its high vitamin C content and bioactive compounds, offers numerous health benefits. Utilizing acerola juice in the formation of water-in-oil-in-water emulsion can enhance its application potential and product diversity. This study employed the block-freeze concentration and spontaneous emulsification methods. Factors affecting emulsion properties, such as emulsifier composition and concentration, water-in-oil emulsion concentration, and stirring speed, were systematically investigated, with each subsequent experiment informed by prior results. The results demonstrated the successful fabrication of water-in-oil-in-water emulsion using Tween 80 as the emulsifier at a concentration of 25%, an optimal concentration of 21%, and stirring at 700 rpm for 15 min. The resultant emulsion exhibited a small droplet size of 0.35 ± 0.01 µm with a polydispersity index of 0.33 ± 0.04. The amounts of total phenolic content, total flavonoid content, and vitamin C, along with DPPH free radical scavenging, indicated significant antioxidant capacity, with values of 5.65 ± 0.05 mgGAE/g, 8.27 ± 0.25 mgQE/100g, 9.17 ± 0.07 mgAAE/g, and 62.78% ± 0.33, respectively.