Microencapsulation of rose essential oil in mung bean protein isolate-apricot peel pectin complex coacervates and characterization of microcapsules

Abstract

Complex coacervates were produced using mung bean protein isolate (MBPI) and apricot peel pectin (APP) and were used as wall material to microencapsulate rose essential oil (REO). The optimal pH and MBPI-to-APP ratio to prepare MBPI-APP complex coacervates were found to be 4.1 and 4:1, respectively. The core-shell morphology of the resulting liquid microcapsules suggested the successful encapsulation of REO in MBPI-APP shell matrix. The encapsulation efficiency, encapsulation yield, and payload values of the freeze-dried REO microcapsules were 89.91%, 87.92%, and 49.95%, respectively. The analysis of Fourier-transform infrared (FTIR) spectra of MBPI, APP, MBPI-APP complex coacervates and REO microcapsules showed an electrostatic interaction between MBPI and APP molecules and the formation of hydrogen bonds between core (REO) and wall components. The REO microcapsules had substantially higher thermal stability compared to free REO. These REO microcapsules were remarkably stable in aqueous, acidic, oily and alcoholic model fluids indicating sustained release capability. The MBPI-APP complex coacervate shell was also stable in oral and gastric stages of in vitro digestion and 65.5% of REO was delivered to the intestinal stage. Furthermore, the shell material produced using MBPI-APP complex coacervates was capable of maintaining the antioxidant capacities of REO during storage.