Drying kinetics of apple pomace by-product using refractance window

Apple pomace is a product obtained by pressing apples to obtain juices and other food products. The valorisation of this by-product is interesting to study because of its composition of bioactive compounds such as dietary fibre and phenolic compounds. The objective of this work was to study the kinetics of drying by the refractance window of apple pomase with a focus on the development of ingredients from this by-product. For this purpose, refractance window drying experiments were carried out with a thickness of 3 mm at three temperatures (70, 80, and 90°C) until reaching a moisture content of 10%. Drying curves, a calculation of effective diffusivity, and the activation energy were constructed. Drying data were modelled using the usual equations for the study of drying kinetics. Drying times varied according to the temperatures applied and times of 420, 330, and 270 minutes were obtained, respectively. On the other hand, the effective diffusivity data were within the usual thin film drying of vegetable products with values of 1.48, 1.85, and 2.92 × 10-10 m2/s. Finally, regarding the modelling of the drying data, the best fit was obtained using the Weibull model. In conclusion, refractance window technology allows the processing and valorisation of apple pomace resources that can be used in different food formulations by contributing its bioactive compounds.