Evaluation of the microencapsulation process of conidia of Trichoderma asperellum by spray drying

Abstract Microencapsulation of biological control agents by spray drying (SD) has been studied as a method for increasing product shelf life and stability to enable the application of microencapsulated agents in sustainable agriculture. In this study, the microencapsulation of Trichoderma asperellum conidia by spray drying was evaluated. The objective was to assess the influence of drying air temperature and wall material (maltodextrin DE20, MD20) concentration on the microencapsulation of Trichoderma asperellum conidia and to identify the optimum conditions to produce. Microparticles were characterized in terms of morphology, particle size, and shelf life. A central composite rotatable design (CCRD) was used to investigate the effect of operating parameters on drying yield (DY), moisture content, conidial viability (CV), and percentage of conidial survival (SP). Microencapsulation experiments were carried out under optimum conditions to validate the obtained model. The optimum temperature and MD20/conidia dry weight ratio were 80°C and 1:4.5, respectively, which afforded a drying yield of 63.85 ± 0.86%, a moisture content of 4.92 ± 0.07%, a conidial viability of 87.10 ± 1.16%, and a conidial survival of 85.78 ± 2.88%. Microencapsulation by spray drying using MD20 as wall material extended the viability of conidia stored at 29°C compared with the control.