Spouted bed performance on drying of an aromatic plant extract

In this study, the spouted bed performance during drying of an extract of the aromatic plant Lippia sidoides has been investigated. The effects of the several processing variables, namely the inlet temperature of the spouting gas (Tge), the feed flow rate of the extract relative to the maximum dryer evaporation capacity (Ws/Wmax), the percentage of drying carrier (Adj), and the percentage of colloidal silicon dioxide added to feed composition (SiO2), on equipment performance and product properties were investigated by using a four-factor and three-level Box–Behnken design. Product recovery (R), product accumulation in the bed (Ac), thermal efficiency (η), loss on drying (LD), product moisture content (Xp), water activity (Aw), polyphenol degradation ratio (DPF), and mean powder diameter (dpm) were the responses evaluated. Results demonstrated significant effects of Ws/Wmax, SiO2, and Adj on spouted bed drying performance. Product properties were affected by all variables studied. Feasibility of the spouted bed technology for the dehydration of L. sidoides extract and the product properties depend on the feed composition properties and drying conditions. The spouted bed showed drying performance and product properties that were comparable to the ones obtained in a lab-scale spray dryer.