MATHEMATICAL MODELLING FOR THIN LAYER DRYING OF RAINBOW SARDINE FISH AT DIFFERENT SALT CONCENTRATIONS IN CABINET DRYER
Fish provides a good source of high quality protein and contains many vitamins and minerals; which are almost cheaper than any others type of meat and also availability of large number of people. Fish is an extremely unpreserved food, and both quantity and quality will be reduced after catching the fish. Currently, dried fish products are often simply incorporated in food formulations and through preparation. Drying is the procedure that removes the moisture contents in the composite product up to the certain threshold value by evaporation. Therefore, the objective of this study is to develop a mathematical model for the thin layer drying of rainbow sardine fish at different salt concentrations in cabinet dryer.
Drying experiment
Rainbow sardine fishes were gutted by opening the belly and remove the intestine, washed under running water and salt concentration for 3 hours. The thin-layer drying experiments were performed in cabinet dryer. Various level of drying experiments were studied for moisture ratio of salted fish at drying temperatures of 50 and 60°C with salted concentration is 10, 20% given in Table 1. Prior to each experiment, the drying time period of about 1 hour to provide a steady state based on experimental drying conditions.
Theoretical background for modelling of drying data
The experimental drying data were used to calculate the moisture ratio (MR) is
where Mt, M0 and Me are the moisture content at time, initial moisture content and equilibrium moisture content. These models were tested in MATLAB R2014a software using curve-fitting tool box. Fig.1 shows the drying curves were drawn using moisture ratios at each time point.
Thin-layer drying experiments were conducted to determine the thin layer drying characteristics of rainbow sardine fish at different salt concentrations in cabinet dryer. Three thin-layer drying models were evaluated for their suitability. From these models, the drying results are indicated that Logarithmic model gave best fit among these three models.
