Insight into the structural, chemical and surface properties of proteins for the efficient ultrasound assisted co-encapsulation and delivery of micronutrients

Three different proteinaceous biopolymers, namely, egg white protein (EWP), soy protein isolate (SPI) and corn protein isolate (CPI) were used as protective shell materials to encapsulate micronutrients via an ultrasonic encapsulation technique. It was found that the physicochemical properties of the three protein-based matrices, including surface/total thiol (-SH) content, surface activity and denaturation temperature were the key factors that influenced the shell formation and stability. The EWP and CPI-shelled microcapsules reduced the degradation of the encapsulated vitamins by 20% and 40% after exposure to heating and UV-light irradiation. A double emulsion technique was further developed to co-encapsulate both oil- (vitamin A and D) and watersoluble (vitamin B, C and minerals) micronutrients. In-vitro digestion study showed that the proteinaceous microcapsules enable a sustained release of micronutrients, demonstrating their potential for food fortification applications.