Optimization of the osmotic dehydration of ginger
ABSTRACT: The present research aimed to optimize the process of osmotic dehydration (OD) of ginger with hypertonic sucrose solution employing response surface methodology. A 23 experimental planning was carried out and 17 experimental assays were performed based on three independent variables (temperature, concentration of the osmotic solution and immersion time) and three dependent variables (moisture loss (ML), solids gain (SG) and dehydration efficiency index (DEI)). The selected assay conditions exhibited the preferred DEI value (the highest ML and lower SG), which were considered in the optimization. Assay 16 demonstrated to be the most favorable conditions for the osmotic dehydration of ginger (DEI =1.61) at 40 40 °C, 50 °Brix and 90 minutes of immersion time. Assay 1 performed at 34 °C, 44 °Brix and 120 minutes of immersion time also displayed desirable response (DEI =1.45). Thus, these two assays were evaluated for the presence of thermal-tolerant coliforms: Bacillus cereus and Salmonella sp.. The analyses presented values below the acceptable limits, which assured high quality hygienic and sanitary conditions of the product.