Pickering high internal phase emulsions stabilized by soy protein isolate/pectin complexes for nobiletin encapsulation and in vitro uptake

Nobiletin, a bioactive flavonoid with promising health benefits, faces challenges in its application due to poor water solubility and limited bioavailability. Here, we prepared Pickering high internal phase emulsions (HIPEs) stabilized by soy protein isolate/pectin (SPI/PE) complexes, optimizing SPI/PE concentration and pH to achieve stable emulsions with improved physicochemical properties. The results showed that SPI/PE complexes formed robust, cohesive interfacial layers that markedly enhanced emulsion stability under a wide range of environmental stresses. The encapsulated nobiletin exhibited significantly improved resistance to UV degradation, extended storage stability, and superior thermal stability relative to conventional carriers. In vitro digestion indicated that SPI/PE HIPEs enhanced nobiletin's bioaccessibility. Cellular uptake studies using Caco-2 cells confirmed enhanced absorption of nobiletin, with SPI/PE HIPEs demonstrating higher cellular uptake and greater overall bioavailability. Furthermore, transport studies suggested potential active transport mechanisms for NOB across Caco-2 monolayers, with higher apparent permeability coefficients in the apical-to-basolateral direction. These findings highlight the efficacy of SPI/PE HIPEs in improving nobiletin's stability and bioavailability, offering a promising strategy to enhance the delivery of hydrophobic compounds in functional food and pharmaceutical applications.