Encapsulation of ascorbic acid in liposomes prepared with milk fat globule membrane-derived phospholipids

The production of nanoliposomes is considered to be an effective technology for the encapsulation and controlled release of nutraceuticals and bioactive compounds, as well as for enhancing their stability and bioavailability. Although liposomes are generally prepared with phospholipids from soy or egg, in recent years, there has been a growing interest in the health benefits and functional properties of milk fat globule membrane-derived phospholipids, as these ingredients have become commercially available. The objective of this work was to characterize nanoliposomes prepared with milk phospholipids using microfluidization, and to evaluate their encapsulation behavior using ascorbic acid as a model biomolecule. Liposomes prepared by microfluidization with milk phospholipids showed an apparent diameter of about 100 nm. The incorporation efficiencies for ascorbic acid increased as the concentration of phospholipid-rich powder increased from 5 % to 10 % (w/w). However, from 10 % to 16 % (w/w), the incorporation efficiency reached a plateau value of 26 %. There appeared to be a change in liposome structure from unilamellar to multivesicular/multilamellar vesicles with high levels of phospholipids (16 %) and a high number of passes through the microfluidizer. Storage studies showed less stable dispersions when stored at pH 3 compared with pH 7. After 7 weeks at 4 °C, liposomes stored at pH 3 and pH 7 retained 67 % of the ascorbic acid originally encapsulated, while only 30 % remained when the dispersions were stored at 25 °C. The present work demonstrated that, using microfluidization, it was possible to obtain small, unilamellar milk phospholipids liposomes stable at neutral pH protecting ascorbic acid for at least 7 weeks.