Development of Liposomal Systems for the Encapsulation of Opuntia ficus-indica var. Blanca Buenavista Extracts: Characterization and in vitro Digestion

Abstract Cactus fruits of Opuntia ficus-indica var. Blanca from the Canary Islands (Spain) are abundant in phenolic acids, such as piscidic acid, and flavonoids, including isorhamnetin, quercetin, and kaempferol glycosides, with their highest concentrations found in the fruit peel. Typically discarded as waste, the peel represents a valuable, underutilized resource. This study was aimed at repurposing this tissue as a source of bioactive molecules, which can be encapsulated in liposomal systems to enhance their stability and protect them during in vitro gastro-intestinal digestion. Blanca peel extracts were obtained using environmentally friendly extraction techniques, which were subsequently encapsulated into two liposomal formulations (Liposome A and Liposome B), prepared using ultrasound-assisted methods under different conditions. Liposome A proved to be the most effective system, offering higher encapsulation efficiencies for individual phenolics (82.1–98.4%), smaller particle size distributions (D10: 38–67 nm; D50: 87–128 nm; D90: 306–426 nm), and a more stable zeta potential (− 24.2 to − 20.8 mV). When subjected to in vitro gastrointestinal digestion, Liposome A demonstrated enhanced stability of phenolic compounds, higher recoveries, and significantly improved bioaccessibility, reaching values up to 88.4% compared to the non-encapsulated Blanca peel extract. These findings underscore the potential of liposomal encapsulation as a strategy for developing bioactive ingredients from Opuntia agricultural waste, offering promising applications in nutraceutical and functional food industries.