Heat and mass transport analysis of the drying of freshwater fishes by a forced convective air‐dryer

Abstract

Abstract The drying behavior of different freshwater fishes (with/without scales) is investigated using a simple convective heated air dryer. Drying processes are analyzed to study the kinetics of drying, shrinkage dependent variable effective diffusivity, convective heat and mass transport, and the energy aspect of drying. Among the drying kinetic models, Hasibuan–Daud and Haghi–Angiz‐I models produce the best fit for fishes with scales and Hii model produces the best fit for fish without scales. Diffusion analysis performed based on simplified solution of Fick's diffusion equation shows higher effective diffusivity for fish without scales, proving additional barrier from scales (for fish with scales) that need to be considered during dryer design. Calculated instantaneous heat and mass transfer coefficients (different for fish with or without scales) also agree with this observation, accentuating the difference based on scales. Drying process for all fishes obeys the heat‐mass transfer correlation. Estimated parameters such as effective diffusivity (0.2–1 × 10 −9 m 2 /s) and convective heat and mass transfer coefficients (7–14 W/m 2 /K and 2.8–4.5 × 10 −6 m/s, respectively) can be utilized in designing different fish drying systems. Average and instantaneous total energy consumption, specific moisture extraction ratio, and specific energy consumption are evaluated in order to provide a comprehensive picture of the drying process. Practical Applications Fresh‐ and salt‐water fishes account for major sources of protein‐rich food for substantial parts of the population in underdeveloped and developing nations. To circumvent the wastage associated with microbial contaminations during prolific seasons, fish drying has been widely employed as a way of preserving this perishable food. Convective drying of agricultural products as well as marine foods is a commonly employed drying method for food preservation. This study investigates the drying behavior of three different freshwater fishes using an in‐house constructed forced convective air dryer. The experimental drying characteristics and estimated parameters by model fitting during fish drying will be particularly applicable in the wide field of fish drying. The outcome of this study can also be utilized for more effectively designing and evaluating low‐cost convective fish dryers.