Self-assembly properties of enzymatically treated oat oil

The enzymatic modification of natural oat oils enriched with polar lipids (PL), consisting mainly of equal mixture of phospholipids and galactolipids, offers a sustainable pathway to produce liquid crystalline phases (LCPs) with diverse structural arrangements, including micellar or bicontinuous cubic and hexagonal phases. These self-assembling lipid systems have potential applications in drug delivery, nutraceuticals, and food formulations due to their ability to encapsulate bioactive compounds, thereby enhancing their stability, and facilitate controlled release. This study introduces a novel, low-energy, and sustainable one-step enzymatic process that makes oat oil lipids self-assemble into desired types of LCPs without the need for additional surfactants or stabilisers. The polar lipid content was a critical factor in determining the curvature of the lipid-aqueous interface and hence the type of LCP formed. Small angle x-ray scattering (SAXS), cryogenic transmission electron microscopy (cryoTEM), and thin layer chromatography (TLC) was used to elucidate the phase behaviour, structure, and composition of the LCP. Functional additives, such as curcumin, vitamin D, and octyl glucoside (OG), were incorporated into the LCPs with concentrations up to 10 wt%, thereby highlighting the possibility to tailor the system for different applications. Dispersed LCP nanoparticles were successfully produced via sonication and have an internal hexagonal structure as verified by SAXS and cryoTEM. The obtained results show that enzymatic processing using lipolytic enzymes can be used to control the conversion of oat oil with the polar lipid content ranging from 15 to 60 wt% into LCPs with either lamellar, micellar cubic (Fd3m) or reversed hexagonal internal structure. • Enzymatic treatment of polar lipid-rich oat oil led to self-assembling lipid systems. • The amount of polar lipids steers formation of liquid crystalline phases. • Functional additives were successfully incorporated in the lipid systems. • Lipolysis of oil is a tool for developing future lipid formulations. • Formulations can be used e.g. for controlled drug-release.