Drying kinetics and characteristic drying curve of lightly salted sardine (Sardinella aurita)

Drying of lightly salted sardine (Sardinella aurita) was accomplished using three air temperatures (35degreesC, 40degreesC, 50degreesC) and three air velocities (0.5m/s, 1.5m/s, 2m/s); the effects of drying conditions on drying kinetics were studied. As for all biological products, air temperature is the main factor influencing the drying kinetics. However, over a given temperature which seems to correspond to protein modification (50degreesC), and at a high air flow rate (2 m/s and 2.5 m/s) a crust formation on the surface of the fish, due to the combined effect of heat and salt was observed. This phenomenon inhibited the drying rate. From the drying curves, two falling rate periods were observed. The dimensionless drying rate versus a dimensionless moisture content data were regressed by the Marquardt Levenberg non-linear optimization method to obtain an empirical equation describing the salted sardine characteristic drying curve.