Optimization of enzyme-assisted hydrodistillation for extraction of nutmeg essential oil and preparation of nutmeg essential oil/porous starch/sodium alginate microcapsules and study of its release behavior

Nutmeg essential oil (NEO) possesses various biological activities, its application is restricted by its high volatility, strong odor, and low water solubility. This study aimed to use cellulase-assisted hydrodistillation to extract NEO. Subsequently, porous starch (PS) served as the carrier to load NEO to form NEO/PS solid microspheres and then sodium alginate (SA) was used as a coating agent to prepare NEO/PS/SA microcapsules. The optimal technology condition of cellulase-assisted hydrodistillation was enzyme addition amount of 1.2%, enzymolysis temperature of 45 °C, pH of 4.0, liquid to material ratio of 13 mL/g, enzymolysis time of 47 min, and distillation time of 193 min, obtaining a yield of 10.69%. The yield of this method was significantly (P < 0.05) higher than that of hydrodistillation (9.15%), and its extraction time (240 min) was significantly (P < 0.05) lower than that of hydrodistillation (360 min). Moreover, DSC, TGA, FTIR, XRD, and SEM results demonstrated that the microcapsules were successfully prepared. Meanwhile, the relative GC-MS profile of the recovered NEO was largely maintained after encapsulation. Additionally, the release of NEO in the microcapsules could be controlled by regulating the temperature and relative humidity. Overall, enzyme-assisted hydrodistillation is a feasible method for the extraction of NEO, and the encapsulation of NEO by PS and SA is an effective means to maintain quality and durability.