Experimental study on foam mat drying of shrimp meat and evaluation of thin-layer drying models

The foam mat drying is a process in which liquid food is converted in to stable foam by combining gas into it, and then dried at a relatively low temperature. The effect of drying temperature (50, 60 and 70 °C) and thickness (4 and 8 mm) on foam mat drying kinetics of shrimp under hot-air drying was investigated. The drying curves obtained were processed for drying rates to find the most convenient model among the 12 different expressions proposed by earlier authors. In addition, the various statistical parameters such as: R2, reduced chi-square, SSE and root mean square error (RMSE) were used to determine the quality of the fit. The colour change during concentration processes was investigated. Total colour differences parameter was used to estimate the extent of colour loss. The zero-order, first-order and a combined kinetics model were applied to the changes in colour parameters. Based on the results, Midilli model was found to be the best model fitted to the experimental hot air drying data at all temperature levels. These models exhibited the highest value of R2 and the least RMSE, χ2 and SSE comparing to the other models. Results indicated that variation in TCD followed combined kinetics model. This model implied that the colour formation and pigment destruction occurred during foam mat drying process of shrimp.