Liposomal system based on lyophilization of a monophase solution for stabilization of bioactives from red onion skin

Encapsulation of obtained polyphenolic extract from red onion skin was performed in phosphatidylcholine-based liposomes based on freeze-drying of the single-phase solution using tert-butyl alcohol-water cosolvent system. The highest amounts of anthocyanins and polyphenols extraction were obtained at 60% ethanolic media without acetic acid. Two batches of nanoliposomes, loaded with obtained bioactives, yielded the nanoliposome particle size of 159.4–177.3 nm, PDI of 0.65–0.7, and zeta potential of −38 to −28.6 mV. The encapsulation efficiency of the prepared nanoliposomes was reported to be higher than 68.42%. The samples exhibited higher stability at 4 °C than 25 °C during 21 days of storage. The spherical and uniform shape of the nanoliposomes and the interactions between the anthocyanins and the nanoliposomes were confirmed by TEM and FTIR tests, respectively. As for the anthocyanin release in the two hydrophilic and lipophilic food simulants, the results indicated the higher release of the anthocyanins in the hydrophilic solution. In general, the liposomal system used for encapsulating poly phenol rich extract from red onion skin can be applied for control release in food products. •Ethanolic solutions (60%) without acid was found to be more efficient in phenolics extraction.•The extract was loaded in nano sized liposomal system based on lyophilized monophase solution.•Liposomes presented high encapsulation efficiency and long term cold storage stability.•Nanoliposomes developed in this study are suitable for food applications.