Nanoencapsulation of Multiple Micronutrients (Vitamin A, D,and Folic Acid, Mineral: Calcium and Iron) Using a DoubleEmulsion Method

Co-encapsulation enables the simultaneous delivery of multiple micronutrients through a single controlled-release system, offering potential synergistic health benefits. However, scaling up the co-encapsulation of multiple micronutrients remains challenging and requires further investigation. This study reports, for the first time, the co-encapsulation of five micronutrients using a biopolymer composite consisting of red rice starch (RRS; 85%) and whey protein isolate (WPI; 15%) as the coating material. Vitamins A and D, folic acid, calcium, and iron were successfully co-encapsulated using a waterin-oil-in-water (W/O/W) double emulsion technique. While single-micronutrient encapsulation achieved efficiencies of up to 100% for vitamin A, co-encapsulation of all five micronutrients reduced the encapsulation efficiency of vitamin A by 49%. In contrast, the encapsulation efficiency of calcium increased by 11% under co-encapsulation conditions. Particle size analysis (PSA) and scanning electron microscopy (SEM) confirmed the formation of nanocapsules with an average diameter of 105 nm. Stability studies demonstrated that the nanocapsules remained highly stable under acidic conditions (pH 1), with only 12.8% of the encapsulated content released after 1 h, indicating their potential for targeted delivery within the gastrointestinal tract. Unlike conventional approaches that encapsulate individual nutrients, this system integrates both water-soluble (folic acid, iron, and calcium) and lipid-soluble (vitamins A and D) micronutrients into a single stable nanoscale delivery system using high-speed homogenization. Furthermore, the improved encapsulation efficiency of calcium observed under co-encapsulation conditions suggests a potential synergistic interaction within the RRS–WPI biopolymer matrix.