Pickering Emulsion Stabilized by Pueraria lobata-Based Stabilizer: From a Passive Carrier to an Active Partner for Oral Capsaicin Delivery

Capsaicin is a bioactive substance with diverse health-promoting properties, but its intense pungency and irritant side effects limit oral application. This study developed a Pueraria lobata particle-based Pickering emulsion (PE) as an oral delivery platform for capsaicin. Modified Pueraria lobata particles (MP-ps) were prepared using a microwave-assisted enzymolysis technique (15% hydration, 252 J/g microwave energy and 8 h pullulanase hydrolysis). MP-ps exhibited surface cracks and pores, altered starch crystallinity, and enhanced water-holding capacity and swelling power. Compared with original Pueraria lobata particles, MP-ps avoided the burst release of puerarin in the upper gastrointestinal tract, dropping from approximately 54% to 20%. An optimized capsaicin-loading PE with excellent physical stability was obtained from 4% MP-ps and a 9:1 (v/v) water-to-corn oil ratio, exhibiting complete core–shell architecture and oil-phase sequestration of capsaicin in TEM images. Gastrointestinal transit analysis in male KM mice indicated that MP-p-based PE reduced the exposure of the encapsulated lipophilic substance in the stomach and small intestine and promoted its accumulation in the colon. Irritation assays in male KM mice and Sprague-Dawley rats further demonstrated that this effective encapsulation alleviated the gastrointestinal irritation of capsaicin and improved its palatability. This study provided a food-derived material and an easy-to-build PE platform for oral lipophilic/irritant substance delivery, with potential for future health-regulating applications.