Impact of freezing-thawing and osmotic dehydration as pretreatments on the convective drying of umbu slices (Spondias Tuberosa arr. Câmara): mathematical modeling and evaluation of physical quality parameters

The umbu (Spondias tuberosa) is an endemic fruit from Brazil, of significant socioeconomic importance, widely consumed in its region of origin, but with a harvest limited to a few months. This necessitates conservation strategies to ensure the availability of the product during the off-season, with freezing and osmotic dehydration (OD) being two effective approaches for preservation and value addition. In this context, studying the combination of freezing and dehydration is crucial, as it extends the product's shelf life and offers flexibility in optimizing the drying process. This study evaluated the impact of freezing-thawing pretreatment and different OD conditions (varying sucrose concentrations and temperatures) on the convective drying of umbu slices, focusing on the physical characteristics of the final product. The research involved mathematical modeling of drying kinetics and process optimization. The results showed that the empirical models of Page and Silva et al. appropriately fitted the drying behavior of the slices. The freezing-thawing pretreatment, combined with drying at 60°C, resulted in higher retention of solids, firmness, and color in the slices, providing an effective approach to optimize the drying process and control the final product characteristics. This study highlights the importance of combining these two techniques, enabling better preservation of umbu and the production of a high-quality product with greater added value and higher profitability for producers.