Microencapsulation of laurel essential oil with chitosan for enhanced durability and antimicrobial properties of leather footbeds

Abstract

This work aimed to produce microparticles (MPs) containing laurel essential oil using the spray drying method, optimize the spray drying process, and evaluate the antimicrobial properties and potential application of these microparticles on leather footbeds. Laurel essential oil (LEO) was preferred due to its high antimicrobial potential and was microencapsulated with chitosan using the spray drying method. Microparticles were applied to leather according to two different methods, i.e., dip-coating and spraying. SEM micrographs showed that all the microparticles had round shape, smooth surfaces, and narrow particle-size distribution attributed to the pre-emulsification process. Among all, formulation L₅ (1:1 (w/w) chitosan: LEO with 20% surfactant) exhibited superior features, including a 12 µm D_50% particle size, a narrower particle-size distribution, and a higher production yield (33%) compared to other formulations of microparticles. The encapsulation efficiency and in vitro release studies of the microparticles indicated that L₅ microparticles exhibited high encapsulation efficiency of 90%, with the release of LEO increasing over time, gradually. Microbiological tests on footbeds revealed that, among all the examined microorganisms, dip-coating samples with LEO exhibited the most potent activity against Candida albicans. In flex resistance tests, it produced zones of 12 + 13 mm, and in dry and wet rubbing tests, it demonstrated zones of 12 + 10 mm. This indicated a high efficacy even after substantial use of the leather footbeds. The work concluded that the developed microparticles were effective for antimicrobial applications on leather footbeds, particularly against Candida albicans.

Graphical abstract