A Study on a Drying Rate of Fish Flesh

Abstract

Drying rates of tuna flesh were measured at several conditions such as temperature, thickness of flesh, air velocity. Relationships between the drying rate and w/w_o, a ratio of moisture content at any time to the initial based on equilibrium, were asymptotic to a straight line independently of flesh thickness at a constant temperature. It was supposed from this result that a layer of an approximately same thickness with steep gradient of moisture content was formed at the surface of flesh in the early stage of drying. Then assuming that a drying rate is determined by a resistance of moisture through the layer, a rate equation was derived. The equation was well coincidence with experimental results. The rate was inversely proportional to the thickness of flesh, different from most of previous workers.