Anais do Simpósio Latino Americano de Ciências de Alimentos
Proceedings of 14 SLACA - Latin American Symposium on Food Science

The inland fish production in Brazil has significantly increased in the last few years. The Arapaima gigas (pirarucu) stand out among the amazon fish species due to the quality of its meat and versatility for culinary uses. Salted/sun-dried A. gigas is a traditional food mostly found in local markets of the Amazon region. This work aims to study the wet salting and the dehydration by microwave vacuum drying and convective drying kinetics of A. gigas. Fish loins were cut into regular pieces (30*30*10mm) and salted in a 20% NaCl brine for 24 h at 4 °C. Sodium chloride gain, mass gain, water gain, and water activity were determined in regular intervals during processing. The Midilli model was fitted to the salting data and used to determine the processing time necessary to produce fish cuts of about 5g of NaCl/100g used to perform the drying process, i.e. 23 min. Drying was performed in an adapted domestic microwave oven with a rotatory drum that operated under vacuum at 120 and 240 W power and by convective drying in an air circulation oven at 50 °C. The samples were analyzed for moisture content, weight loss, water activity, and color properties (L*, a*, b*). The drying time to reach a moisture content of about 30 g water/100 g was approximately 20 h for convective drying, 56 min and 20 min for microwave vacuum drying at 120 W and 240 W, respectively. The microwave vacuum dried samples presented higher values of lightness (L*) and lower values a* and b* compared to convective dried samples. Microwave vacuum drying is an alternative to producing salted/dried A. gigas in shorter times and lighter colors than convective drying.