Nanoencapsulation of limonene in octenyl succinic anhydride-modified starch (OSA-ST) and maltodextrin: Investigation and comparison of physicochemical properties, efficiency and morphology of nanoparticles

In recent years, the application of nanoencapsulation has attracted enormous attention for various food and pharmaceutical purposes. In this study, a functional powder containing limonene (the nutraceutical at concentration of 5 and 10 %) was prepared using octenyl succinic anhydride-modified starch (OSA-ST) and maltodextrin as carriers at 15 and 30 %. The emulsions were sonicated at a frequency of 30 kHz and a power of 100 W for 9 and 18 min, and the final nanoparticles were prepared through freeze-drying. The particle sizes were in the ranges of 62-248 and 10-24 nm in the suspensions of OSA and maltodextrin, respectively. The smaller particles of the maltodextrin-prepared sample resulted in more transparency. The zeta potential and consequently the stability of the maltodextrin-prepared emulsions were higher than those of the OSA-ST-prepared ones. As the maltodextrin concentration increased, this parameter was elevated from -42 to -36 as a result of the coverage of the surface-active lipids. The results of solubility correlated with those of the zeta potential (89.21 % for maltodextrin-prepared and 82.51 % for OSA-ST-prepared samples). The highest encapsulation efficiency (EE = 0.9) belonged to the samples prepared with OSA-ST. Comparison of the scanning electron microscopy (SEM) images revealed that the type of the wall material influenced the physical structure of the nanoparticles which were mostly porous and flake-like. Considering its encapsulating-emulsifying properties, OSA-ST can be suggested as a carrier for limonene with the need for emulsifiers.