Development and characterization of niosomal delivery system for betalain-rich extract from prickly pear (Opuntia ficus-indica L.)

Betalains are secondary metabolites that support their use as natural food colorants. Niosomes have been applied as encapsulation systems to enhance betalain stability. This study aimed to encapsulate betalain-rich extract from prickly pear using a niosomal system, with process parameters optimized by response surface methodology (RSM). Niosomes produced under optimum conditions were characterized. Optimum encapsulation was achieved at a Span 60:Tween 80 molar ratio of 1.161, 14.44 mg extract/100 mg surfactant, 0.1 mg cholesterol/100 mg surfactant, and 89.99 s ultrasonication. Under these conditions, encapsulation efficiency and TBC were 96.06% and 687.301 mg betalain/kg dry matter, respectively. Characterization results were consistent with model predictions. Following in-vitro gastrointestinal digestion, niosomal formulations enhanced the stability and controlled release of phenolics and betalains compared to the extract alone, rather than increasing their apparent total content. Overall, niosomal encapsulation represents a promising strategy for stabilizing betalain-rich extracts, offering potential as natural alternatives to synthetic food colorants while meeting consumer demand for functional ingredients.