Structural State and Form of Free and Biopolimer-Encapculated Phosphatidylcholine Lipisomes in the Absence and Presence of Natural Plant Antioxidants
Using ESR and atomic force spectroscopy, we have studied liposomes prepared from soybean phosphatidylcholine with the incorporated plant antioxidants (extracts from ginger, allspice and black pepper, pimento) and encapsulated in biopolymers (sodium caseinate or the sodium caseinate-maltodextrin covalent conjugates). With ESR and 16-doxylstearic acid spin probe we have found that plant antioxidants decreased microviscosity of the deep-lying regions of the lipid bilayer of liposomes by 15-25%. Ginger extract exerted the highest effect (24%). Sodium caseinate and the sodium caseinate-maltodextrin covalent conjugates (using maltodextrins of dextrose equivalents such as 2 and 10) caused a 30-35% increase in microviscosity in regard both to free liposomes and liposomes with antioxidants. Using atomic force microscopy, we have shown that the incorporation of antioxidants leads to an increase in the area of cross-section and the volume of liposomes, and encapsulation in polymers results in liposome thickness and the formation of more compact structure.