OPTIMIZATION OF APPLE DEHYDRATION THROUGH PRETREATMENTS FOR SENSORY QUALITY

In the city of São Paulo, approximately 18,400 tons of food from street markets are discarded annually, with fruit seasonality being another factor that contributes to surpluses and post-harvest losses. Dehydration is an efficient and low-cost alternative to extend the shelf life of fruits such as apples. However, enzymatic browning compromises quality, making pretreatments essential to preserve sensory characteristics. The main objective of this study was to evaluate the drying kinetics of apple slices and the sensory quality of the product, investigating the influence of the drying profile on sensory attributes. Gala apple (Malus domestica 'Gala') slices, 2–3 mm thick, were used in triplicate and immersed for 10 minutes in four solutions: control (water), citric acid (1%), sucrose (30%), and the combination of acid + sugar. The samples were dried in a dehydrator at 60 °C until reaching hygroscopic equilibrium (weight variation ≤ 0.01 g). Color analysis was performed before and after drying using a colorimeter, and water activity (Aw) was measured at the end of the process using an Aqualab. The drying kinetics were fitted to mathematical models, with the best model selected based on the highest coefficient of determination (R²) and the lowest mean relative error (MRE) and standard deviation of estimate (SDE). The results confirmed the high efficiency of the process, with all samples reaching Aw < 0.50, a value that minimizes deterioration reactions. Colorimetry showed that pretreatments with pure sucrose (L* = 73.67, a* = −0.13) and the combined treatment (L* = 74.42, a* = 0.23) were the most effective, as they preserved color by inhibiting oxidation through the osmotic effect of sucrose, which also helped accelerate drying. However, citric acid alone was insufficient, showing browning similar to the control (L* ≈ 62.90, a* ≈ 5.42). Regarding drying kinetics, the Cavalcanti Mata model provided the best fit (R² = 0.99 and MRE = 3.60×10⁻⁴) for all treatments. This result allows for accurate prediction of drying time, optimizing energy consumption and ensuring final product quality. It is concluded that the drying kinetics modeled by Cavalcanti Mata directly influenced sensory quality. The sucrose pretreatment, by optimizing the drying profile, was crucial to preserving color and proved to be the most efficient strategy, ensuring microbiological and sensory quality with lower energy consumption.