Preparation, characterization and release behavior of chitosan-coated nanoliposomes (chitosomes) containing olive leaf extract optimized by response surface methodology.

This study was dedicated to the optimization and preparation of chitosan-coated liposomes (chitosomes) as promising nanocarriers for retention of olive leaf extract optimized by Response surface methodology (RSM) based on central composite design. Accordingly, the best sample was chosen for further tests with the encapsulation efficiency, stability and electrical conductivity of 94%, 98% and 9.545 mS respectively. The average size of the optimal chitosome and nanoliposome were lower than 100 nm and the zeta potential was altered from a negative charge to positive after addition coating process with chitosan. Moreover, the differential scanning calorimetry of blank and loaded chitosome revealed the increase of fluidity and lower temperature of phase transition in loaded chitosome compared to blank one. FTIR spectra demonstrated that electrostatic interactions and hydrogen bonds occur between phospholipid polar groups, chitosan amine moieties and major olive leaf extract polyphenols including oleuropein and hydroxy tyrosol. Furthermore, the optimal loaded chitosome had the highest stability during 25 days at the temperature of 4 °C. Finally, the in vitro release tests were best fitted with Peppas-Sahlin and Kopcha models in food simulants and gastrointestinal simulated juice respectively revealing erosion-based release model. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s13197-021-04972-2). © Association of Food Scientists & Technologists (India) 2021.