Nanoencapsulation of hyssop essential oil in chitosan-pea protein isolate nano-complex

Abstract

Nanoencapsulation of bioactive compounds is an emerging field in food and pharmaceutical industries. In present work, essential oil was extracted from aerial parts of hyssop and encapsulated in chitosan-pea protein isolate nano-complex using a nanoprecipitation method. A central composite design (CCD) was employed to optimize the formation of nano-complex for maximizing the retention rate of hyssop essential oil (HEO) loaded in the nano-matrix and minimizing the average particle size simultaneously. The optimum nano-matrix formation were of chitosan/pea protein isolate ratio of 2.12 (w/w) and essential oil/chitosan-pea protein isolate ratio of 1.88 (w/v). Under these conditions, the retention rate of HEO and the average particle size were 81.2% and 216.4 nm, respectively. Furthermore, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses indicated the success of HEO encapsulation. The formed nanoparticles illustrated a spherical shape and regular distribution as indicated by scanning electron microscopy (SEM). The antioxidant activity of HEO-loaded chitosan-pea protein isolate nano-complex was higher than free HEO. Similarly, the encapsulated HEO had a high antifungal activity against Botrytis cinerea under both in vitro and in vivo conditions. The encapsulated HEO at 2 mg/mL concentration significantly decreased both the incidence and disease severity of gray mold on strawberries during storage at 4 °C. These findings imply that HEO-loaded chitosan-pea protein isolate nano-complex is a promising case to be used for novel applications in pharmaceutical and food industries.