Co-delivery of bioactive compounds in W/O high internal phase emulsions: Stability, in vitro digestion, and cytotoxicity.

Water-in-oil high internal phase emulsions (W/O HIPEs) are emerging as promising vehicles for low-calorie formulations and incorporation of bioactives. This study evaluated W/O HIPEs to co-deliver β-carotene and catechins from green tea extract (GTE), focusing on stability, in vitro digestion (lipid hydrolysis and bioaccessibility), and cytotoxicity. W/O HIPEs remained macroscopically stable (no phase separation) for 60 days, although significant droplet coalescence was observed, more pronounced in catechin-loaded HIPEs stored at 23 °C. W/O HIPEs exhibited gel-like behavior, contributing to resistance under gastric conditions, with phase inversion occurring only during intestinal digestion, where 80-95% free fatty acids were released. Bioaccessibility of β-carotene improved from 37% (free form) to 65-73% after incorporation and reached 99% when co-delivered with catechins from GTE. Catechins´ bioaccessibility increased from 9% to 14-31%. In vitro digested W/O HIPEs showed no reduction in metabolic activity of differentiated co-cultures, supporting their potential applicability in functional foods.