Antimicrobial and insecticidal activity of spray dried juniper berry (Juniperus communis L.) essential oil microcapsules prepared by using gum arabic and maltodextrin

This study was carried out to optimize spray drying conditions for juniper berry essential oil (JBEO) microencapsulation. The coating material for encapsulation was a combination of maltodextrin (MD) and gum arabic (GA). The wall material content, inlet air temperature and feed flow rate were optimized to obtain small particle size and high level of powder production, with high JBEO loading and encapsulation efficiency, small powder moisture and hygroscopicity. The optimal formulation was characterized by FTIR spectroscopy and used for investigation of antimicrobial and insecticidal activities. The obtained optimal conditions for JBEO microencapsulation were inlet air temperature of 140 degrees C, feed flow rate of 2.43 cm(3) min(-1) and wall/core ratio of 3:1. The considerably greater JBEO oil retention was obtained by using spray dried GA compared to GA in a form of the branched polysaccharide. Microencapsulated JBEO showed antibacterial and antifungal activities at oil concentrations 1-5 %. Strong repellency against S. oryzae and A. obtectus were achieved at concentration of JBEO of 2 %, while for mortality of 65.5 % (S. oryzae) and 85.5 % (A. obtectus) after 72 h, the 5 % of JBEO were required. JBEO microencapsulation could be a promising method for the production of biopesticides to reduce the use of chemical preparations.