The response surface methodology: An application to optimize dehydration operations of selected agricultural crops

Optimization is an essential tool in food engineering for the efficient operation of processing systems and unit processes yielding a highly acceptable product. The response surface methodology approach is a statistical technique that was used by authors in most studies involving optimization. The same methodology was used to optimize several unit operations in food process engineering using ftactional factorial experimental designs. The processing operations included: drying, juice extraction and compaction with parameters affecting the process as independent variables while the responses (to the parameters), designated as dependent variables. An analysis of variance (ANOVA) was usually performed to determine which of the parameters significantly affected the independent variables. Second order polynomial (SOP) models as functions of the independent variables generated response surface and contour plots. Optimum regions were derived by superimposition of the contour plots based on industry standards. Separate validation experiments were conducted at optimum conditions to verify predictions and adequacy of the SOP models. Optimization studies in hot air-drying and vacuum dehydration are presented in this paper. Optimum conditions of 68 degreesC and 10 KPa for 1.6 mm strips were established for vacuum dehydration of carrots while a 70 degreesC drying temperature for the hot air-drying of 2 mm garlic slices. (C) 2002 Published by Elsevier Science Ltd.