Liposomes made from soy phosphatidylcholine entrapping food waste compounds (collagen hydrolysate, L-HC; pomegranate peel extract, L-PG; and shrimp lipid extract, L-SL) were freeze-dried and stored for seven months. The freeze-drying process increased the particle size and decreased water solubility. The freeze-dried L-HC and L-PG preparations presented large multivesicular vesicles with spherical and unilamellar morphology. Large multilamellar vesicles were observed in L-SL, coinciding with greater structural changes in the membrane bilayer and increased thermal stability, as observed by ATR-FTIR and DSC. Dynamic oscillatory rheology revealed a slight hardening in the dried liposomes, induced by storage time. A sharp rigidifying effect in the temperature range from 40 to 90 °C was observed in L-SL. The loading with antioxidant compounds prevented freeze-drying-induced lipid oxidation. The storage stability of freeze-dried liposomes and their technological aptitude as a food ingredient varied depending on the chemical nature of the entrapped compounds.

The authors wish to thank the Spanish MINECO for financial support (project AGL2014-52825).

Peer Reviewed