Water-in-oil nanoemulsions as a delivery system for polyphenolic compounds from edible flower and fruit matrix: Modulating bioaccessibility, bioavailability, and health benefits by in vitro

Water-in-oil nanoemulsions are a potential form of polyphenol encapsulation, but their use remains limited. Therefore, the aim of this study was to assess the possibility of encapsulating different doses of polyphenolic extracts isolated from chokeberry, rosehip, black mallow, and marigold using nanoemulsions prepared with Ultra-Turrax homogenization followed by ultrasonication. The use of a wide range of materials enabled the introduction of a diverse profile of polyphenols (i.e., anthocyanins, phenolic acids, flavonols, and flavan-3-ols) into the emulsion. Flavan-3-ols and phenolic acids demonstrated higher ability to encapsulate, while anthocyanins negatively affected emulsion integrity. Rosehip and marigold extracts showed the highest encapsulation capacity, maintaining compound ratios and physical properties. Simulated digestion revealed that nanoemulsions protect polyphenols, enabling targeted intestinal release and improved absorption. However, anthocyanins degraded significantly, highlighting the need for alternative emulsifiers. Nanoemulsions exhibited enhanced antioxidant activity and strong α-amylase inhibition, although no significant effects were observed against α-glucosidase or pancreatic lipase.