Physicochemical study of the conservation of Moroccan anchovies by convective solar drying

Abstract

Local fish markets are often saturated during periods of full production. Solar drying offers a suitable alternative to reduce losses of surpluses, and to preserve products for a longer period. In this respect, this work was carried out to study the effect of the air indirect solar convective drying process on the dehydration kinetics of anchovy. Experimental drying kinetics was measured at four air temperatures (50, 60, 70 and 80 °C) and for a constant air flow of 300 m3/h. The moisture desorption isotherms of the anchovy were determined at three temperatures (30, 40 and 50 °C), using the static gravimetric method to determine the optimum water activity for conservation of the nets anchovy. Experimental results showed that the drying kinetics of the anchovy was accelerated synchronously with the increase of the air temperature. The value of optimal water activity for conservation of anchovy is aw = 0.30 and the desorption isotherms suggest a non spontaneous process. Nine drying models were adapted to the drying data; the Logarithmic model allowed better adaptation than the other models. The effective diffusion coefficient value Deff determined by Fick’s second law varied from 3.84 10−9 to 5.60 10−9 m2/s and the activation energy value was Ea = 12.90 kJ/mol.