Uso de la liofilización y la convección como métodos de secado del subproducto del xoconostle y el efecto sobre sus propiedades antioxidantes

Abstract

In this study, the influence of the drying method (lyophilization and convection) on the techno-functional and antioxidant properties of the by-product of xoconostle cv. Cuaresmeño (Opuntia matudae) was evaluated. During convection drying, the effect of the temperature (60, 70 and 80 °C) was evaluated, resulting in drying times of 195, 165 and 120 minutes, respectively. The influence of the temperature on the equilibrium humidity was determined through the drying kinetics, which were affected by increasing the temperature from 60 to 80°C. The drying time for the by-product decreased, and equilibrium humidities of 0.04, 0.03 and 0.02 g water/g dry sample were reached for 60, 70 and 80 °C, respectively. Fick's second law was used along the experiments to determine the effective diffusivity, which ranged from 4.788 E-10–8.109 E-10 m2/s for the evaluated temperatures. Convective drying at 60°C proved to be a suitable alternative for the conservation of antioxidant capacity (88.07 ± 0.38% 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition) compared to drying at 70 and 80°C. These were 8% higher compared to the results for freeze drying. However, convective drying at 60°C is more convenient for the xoconostle by-products due to the cost-benefit ratio.