Nisin induces lamellar to cubic liquid-crystalline transition in pectin and polygalacturonic acid liposomes

Liposomes modified with biomolecules can present better stability and specific structural characteristics, representing a profitable alternative to conventional liposomes. In this study, liposomes formulations containing pectin (PT) or polygalacturonic acid (PA) were prepared by the thin-film hydration method and reverse phase evaporation method for nisin (Nis) encapsulation. Liposomes free from nisin were studied as reference. Structural characteristics of the formulations were investigated by differential scanning calorimetry (DSC) and small angle X-ray scattering (SAXS) in the temperature range from 20 to 60 degrees C. The presence of nisin promoted the transition of lamellar to cubic phase, leading to the formation of partial cubosomes dispersions, which presented stability over temperature increase. The association to the polysaccharides did not prevent the cubic phase formation, although different symmetries were produced according to composition, preparation method and temperature variation. The complex network structure of the cubic phases can represent potentially efficient nanocarriers for sustained release of ingredients.