Chickpea aquafaba-stabilised pickering-type emulsions for chilli oleoresin encapsulation: capsaicin release, bioaccessibility and cellular bioactivity following in vitro digestion.

Aquafaba (AF) from cooked British Kabuli chickpeas, containing naturally occurring nanoparticles and denatured proteins generated during cooking, was evaluated as a Pickering-type stabiliser for chilli oleoresin encapsulation and capsaicin delivery. An optimised emulsion containing 15% AF, 6.64% oil phase (1,1 oleoresin, MCT) and 78.36% water was selected due to its high physical stability. Encapsulation efficiencies exceeded 97% for both oleoresins. Particle size and ζ-potential measurements indicated stability during digestion. Low capsaicin release during oral and gastric phases suggested effective protection against early degradation, oral pungency, and gastric irritation. Capsaicin bioaccessibility was similar for capsicum (48.07%) and birds' eye chilli (49.61%) emulsions, although capsicum systems provided higher bioaccessible capsaicin concentrations (83.47 μg/mL) than chilli birds' eye systems (64.28 μg/mL). Micellar fractions from encapsulated oleoresins improved Caco-2 cell viability, antioxidant activity and intracellular ROS inhibition. Overall, AF-stabilised Pickering-type emulsions provided an effective plant-based platform for capsaicin encapsulation and gastrointestinal delivery.