Liposomal propolis loaded xanthan gum-salep hydrogels: Preparation characterization, and in vitro bioaccessibility of phenolics

Abstract

Liposomes are gaining interest in food and pharmaceutical applications due to their biocompatibility and non- toxicity. However, they suffer from low colloidal stability, leakage of encapsulated substances, and poor resistance to intestinal digestive conditions. To address these issues, propolis extract (PE) was encapsulated within a hybrid system combining liposomes and hydrogels. PE encapsulated in phosphatidylcholine liposome formulations incorporated with two different food additives: polyethylene sorbitan monooleate (T80) and ammonium phosphatide (AMP) was embedded in xanthan gum-salep hydrogels. The embedded liposomes protected their structure and did not change the flow behaviour of the hydrogels. AMP-liposomal gels exhibited a stronger solid character. The mucoadhesiveness of liposomal gels was mostly governed by the higher xanthan gum ratio, while PE loading also yielded higher mucoadhesiveness. The bioaccessibility (BI%) of the phenolic compounds ranged from 10.13 to 582.75 % in the liposomal gel. The proposed hybrid encapsulation method not only provided enhanced solubility to hydrophobic PE but also protected its phenolic compounds against simulated digestion conditions. Moreover, converting aqueous liposomes into gel structures would also expand their application range in various functional food formulations.