ANÁLISE DA CINÉTICA DE SECAGEM DA BATATA INGLESA (Solanumtuberosum L.) POR REFRACTANCE WINDOW: APLICAÇÃO DO MODELO DIFUSIONAL E ISOTERMAS DE DESSORÇÃO

Abstract

Tropical tubers are important sources of energy-rich food for human nutrition, playing a relevant role in the socioeconomic context. In addition to providing an independent source of nutrients in the country, it acts as an employment generating activity, leading to sustainable development in the field. In this perspective, drying is an efficient technological alternative to reduce post-harvest losses, since a considerable percentage of the crop is lost due to the inefficiency of transportation, storage and distribution processes. This research was developed with the purpose of evaluating the drying kinetics of english potato (Solanum tuberosum L.) by the method of refractance window, where samples with a thickness of 5 mm were submitted to temperatures of 85, 90 and 95 ° C, the influence of the osmotic-ultrasonic pretreatment, with concentration of the osmotic solution of sucrose of 40 ° Brix, 40 minutes of dehydration and ultrasonic bath frequency set at 40 kHz. In order to adjust the experimental data, the Fick models were applied for diffusion coefficient analysis, Page, aiming to evaluate the drying kinetics, besides GAB and Chung in the determination of the desorption isotherms. The values presented by the respective coefficients of determination (R²) were used to analyze the degree of fit of the models. The Fick model exhibited effective diffusion coefficients compatible with those reported in the literature, where the samples submitted to pre-treatment demonstrated a higher rate of water loss. The equation of Page was effective in the mathematical description of the operation, with a lower R² value equal to 0.9954. In relation to the desorption isotherms, Chung was better fitted to the data, presenting higher determination coefficient in 4 of the 6 experiments. For all the models used the adjustments were high, being suitable in the representation of the drying process.