Synthesis of multivitamin-loaded heat stable liposomes from milk fat globule membrane phospholipids by using a supercritical-CO2 based system

Abstract

Inspired by the heat stability of milk, where fat globules are coated by the milk fat globule membrane (MFGM), heat stable liposomes loaded with multivitamins were successfully synthesized from MFGM phospholipid concentrate. The MFGM phospholipids were first isolated from buttermilk powder, an undervalued dairy byproduct, by means of sequential pure SC-CO₂ and ethanol-modified SC-CO₂ extraction. The final extract was composed of 75% phospholipids, the highest MFGM phospholipid purity reported so far from buttermilk powder. Extracted MFGM phospholipids concentrate was utilized in liposome synthesis by the rapid expansion of supercritical solution using a venturi-based system (Vent-RESS) for vacuum driven cargo loading. Liposome synthesis was also conducted using sunflower phosphatidylcholine (SFPC) for comparison. To test the performance of the liposomes, vitamins E and C were used as model hydrophobic and hydrophilic bioactives, respectively. MFGM phospholipids mostly produced unilamellar vesicular type liposomes with an average diameter of 533 nm and ζ-potential of −57 mV. The encapsulation efficiency (EE) of vitamins E and C in MFGM liposomes were 77 and 65%, respectively. Even after heating at 90 °C for 30 minutes, MFGM liposomes retained structural integrity as shown in their confocal micrographs, structural characterizations, and EE measurements. In contrast, SFPC liposomes disintegrated at temperatures above 60 °C. Thus, MFGM liposomes have the potential to protect the nutritional and functional properties of bioactive compounds during extended exposure to thermal treatment. This study proposes a green method to extract dairy phospholipids and fabricate liposomes for the delivery of bioactive compounds with application in the food, pharmaceutical, and cosmetic industries with a great potential for scale-up.