INFRARED DRYING OF ‘ACURI’ PULP

Brazil presents a great diversity of native species, requiring techniques for preservation and valorization of their biomes, mainly Cerrado and Pantanal. The palm Attalea phalerata Mart. ex. Spreng is native to the central region of Brazil, and its fruit “acuri” presents a pulp rich in proteins, provitamin A and minerals. The infrared drying (IRD) has been investigated as a potential method for the drying of numerous products. This technique increases the effective thermal processing, decreasing drying time with high energy efficiency. The infrared drying behavior of acuri pulp was experimentally investigated in the temperature range from 60 °C to 80 °C. The pulps were obtained from a traditional community (Campo Grande, MS) and stored at -25° C prior the experiments. The IRD (OHAUS balance, MB200 model, Brazil) was conducted at 60, 70 and 80 °C. The experiments were performed in triplicate. The drying rate was found to increase with temperature, hence reducing the total drying time. As drying temperature was raised from 60 ◦C up to 80 ◦C, the time period required to reduce the moisture content of the sample from 1.03 kg H2O/kg down to 0.20 kg H2O/kg (dry basis) was observed to decrease from 160 min to 90 min. Increasing the IRD temperature acceleratesthe process, removing the moisture quickly, and consequently shorter drying time drying is required. The effective moisture diffusivity was obtained using Fick’s second law of diffusion and ranged from 2.21 to 3.30 × 10−10 m2/s over the temperature range. The temperature dependence of the effective diffusivity coefficient was described following an Arrhenius-type relationship. Activation energy for the moisture diffusion was determined as 19.82 kJ/mol. These parameters were in accordance with foodstuffs drying processes. Provided the specific experimental configuration of the present investigation, the IRD was an efficient method for acuri drying.