Optimization of the Freeze-Thaw-Dehydration Process for Dehydrated Instant Potato Cubes

摘要

A process for the production of high quality dehydrated instant potato cubes by freeze-thaw-dehydration technology was optimized. Freezing temperature (FT), thawing temperature (TT) and drying temperature (DT) were determined as the most important factors affecting quality attributes such as true density, hardness, colour and cooking time of the dehydrated potato cubes. A three factor factorial design was used with three levels of each variable. The three independent variables (factors) used in the experiments are freezing temperature: -5, -15 and -25℃; thawing temperature: 1, 5 and 10℃; and drying air temperature: 50, 60 and 70℃. Second order polynomial models were fitted with the experimental data. Optimum range of the process parameters was obtained using Solver Suite. Optimum conditions for the freeze-thaw-dehydration process of 1 cm~3 potato cubes were FT = -24℃, TT = 5℃ and DT = 59℃. Experimentally determined values for response variables viz. true density, hardness, colour and cooking time of the dehydrated potato cubes processed under optimum conditions were found to be very close to the predicted values of 845.54 kg m~(-3),8049.03 g, 61.71 L-value and 93.66 s, respectively, from the model equations developed.