Synergistic Effect of Advanced Refractance Window Drying on Quality Characteristics of Potato Slices and Numerical Process Optimization

The present investigation was aimed to develop an advanced refractance window drying (RWD) method for the drying of potato slices. A total of 17 experiments were carried out by using the Box-Behnken design (BBD) with RWD process parameters, i.e. drying temperature (75 °C, 85 °C, and 95 °C), potassium metabisulphite (KMS) concentration (0.5%, 1.0%, and 1.5%), and potato slice thickness (2 mm, 3 mm, and 5 mm). The effect of RWD process parameters on dehydration ratio, rehydration ratio, shrinkage ratio, total colour difference (TCD), and overall acceptability (OA) was analysed. Design-Expert software (ver. 13.0.1) was employed for numerical optimization of the experimental results. The optimized values for drying temperature (°C), KMS concentration (%), and slice thickness (mm) were found to be 85 °C, 0.5%, and 3 mm, respectively, and the corresponding responses were found to be 4.64, 3.45, 0.361, 9.956, and 4.64 for dehydration ratio, rehydration ratio, shrinkage ratio, TCD, and overall acceptability, respectively. A comparative analysis of optimized RWD (O-RWD) potato slices and conventionally dried (CD) potato slices was also conducted for proximate analysis, total colour difference (TCD), total sugar, textural properties (crispiness and hardness), water activity, and overall acceptability (OA). The results revealed that O-RWD potato slices were significantly higher in protein content, carbohydrates, total sugars, crispiness, and OA compared to CD potato slices. Overall, this study recommended that RWD provided better dried potato slices compared to CD.