Modeling the Rehydration Behavior of Oven and Vacuum Oven Dried Shrimp at Different Rehydration Temperatures and Determination of Quality Parameters

Abstract

In this study, shrimps dried by oven (OD) and vacuum oven (VOD) in the previous study, were rehydrated at temperatures of 30, 40 and 50 degrees C and the kinetics of rehydration during this time were examined and curves are modeled. In rehydration kinetic studies, rehydration contents, rehydration rates, moisture ratio and effective moisture diffusions were calculated. Modeling was done based on Peleg and Two-Term mathematical models from the obtained rehydration curve data, and the results were evaluated statistically using the reduced chi-square (chi 2), coefficient of determination (R2) and root mean square error (RMSE) definitions. Color measurements were chosen as quality parameter analysis and interpretations were made based on the total color changes. When the results were examined, it was observed that all samples reached equilibrium in the 180 and 150 minute in oven drying and vacuum-oven drying, respectively and the sample with the highest rehydration value was observed in the one dried at 80 degrees C in a vacuum-oven drying and rehydrated at 50 degrees C. Since the drying time of the samples dried in the vacuum oven was shorter, their pores were less narrowed and thus they experienced more rehydration. It was observed that the samples were rehydrated more as the rehydration temperature increased. Since the rehydration rate, moisture content and effective moisture diffusivity values are in parallel with the rehydration contents the same increase occurred at these parameters. Looking at the mathematical modeling results, the Peleg model gave better results in samples rehydrated at 30 and 40 degrees C, and the Two-Term model gave better results in samples rehydrated at 50 degrees C. From the total color changes as expected vacuum-dried shrimps total color changes were less than the oven-dried shrimps and the color changes increased as the rehydration temperature increases due to the increase in the lightness values.