Assessment of Parameters to Apply Osmotic Dehydration as Pretreatment for Improving the Efficiency of Convective Drying of Cassava Bagasse

Abstract

This manuscript corresponds to exploratory research carried out to evaluate and define the operating parameters for applying osmotic dehydration (OD) as pretreatment for efficiency improvement in the convective drying of cassava bagasse, providing a methodology to apply these combined techniques, not only for cassava bagasse but also to serve as a reference for its use in other high-moisture agro-industrial residues. Operating factors significant for moisture loss during OD were determined through sieving analysis. Adequate levels and operating conditions were determined for OD and subsequent drying (osmotic agent concentration, solution-to-sample ratio, agitation speed, immersion time, required draining mesh, draining time, drying temperature, and drying air speed). It was established that an osmotic treatment was able to reduce the moisture of cassava bagasse from 87.7% to 28.94% and subsequent drying time by approximately 38.8%. These results allow the use of these combined techniques for drying cassava bagasse, which in turn, open a research agenda for its application in other agro-industrial residues, contributing to its handling, revaluation, and development of a sustainable agro-industry.

Osmotic dehydration of cassava bagasse (Manihot esculenta) and its effect as pretreatment on the efficiency of convective drying

“…Based on the results from Serpa et al (2022), to evaluate the OD effects as a pretreatment to convective drying of cassava bagasse, the OD treatment was carried out using concentrations of 5%, 12.5%, and 20% NaCl of osmotic agent, with solution: sample ratios of 3:1, 4:1, and 5:1; at 320 rpm each, in ambient conditions during a 10 min immersion time. After the OD treatment, the samples were drained for 20 min using a 12-mesh sieve.…”

“…The OD operation as a pretreatment to the convective drying of cassava bagasse, using salt as an osmotic agent, presents restrictions regarding the used NaCl concentration and the drying temperature, limited to a maximum of 20 % NaCl and 40 °C respectively, since at higher concentrations and temperatures, a crust is formed on the sample surface affecting the efficiency of the mass transfer and heat transfer processes, and the decrease in the sample moisture (Serpa et al, 2022).…”