Ascorbic acid encapsulation by complex coacervation of kappa carrageenan and calcium caseinate pretreated by high‐power ultrasound

Abstract Encapsulation by coacervation has received interest in the last few years because of its low cost. Ultrasound (US) processing has proven to be an adequate technology for protein denaturation, increasing coacervation yield. There is a lack of information regarding its effects on encapsulation yield. The aim of this work was to evaluate the effect of US treatments on calcium caseinate (CaCN)–kappa carrageenan (KC) coacervates and the improvements in encapsulation efficiency (EE) of ascorbic acid (AA). US‐treatments (50% and 100% amplitude, 2 and 4 min) were applied to a 2% CaCN solution. Caseinate solution was mixed with a soy oil–AA (25%) W/O emulsion to form a second emulsion W/O/W. Finally, the second emulsion was employed for complex coacervation with KC (2% solution). The results showed a 10% increase in EE in the US‐treatments, with better stability and release profiles compared to the control. Sonication proved to be effective for coacervation improvement. Practical Applications Ultrasound pretreatment of calcium caseinate for coacervation along with kappa carrageenan showed an increase in the coacervation yield. This result was mainly attributed to the structural protein modification obtained after ultrasound (US) treatment. These coacervates can be employed to encapsulate bioactive compounds, such as ascorbic acid (AA), which is one of the most labile vitamins. In this sense, the US application leads to increases in encapsulation efficiency (around 10%) with a better stability and release profile than the capsules without treatment. These results create an opportunity to encapsulate AA and use the capsules in systems with a wide range of pH, increasing the chances of having functional products on the market.