Edible coating and counter-current product/solution contacting: A novel approach to monitoring solids uptake during osmotic dehydration of a model food system

In an effort to explore a novel approach to monitoring solids uptake during osmotic dehydration, the combination of product coating with alternative scenarios of product/solution contacting (“flow”) was investigated. Potato was used as a model plant material for short term (i.e. 3 h) osmotic treatment in a series of sucrose solutions with decreasing or increasing concentrations to simulate co-current or counter-current product/solution contacting (flow), respectively. A mixed-level full factorial experimental design was used. Data were analyzed using multiple linear regression procedures. Counter-current product/solution contacting contributed to faster water loss and slower solids uptake. In both flow-types, initial solids had a significant impact on both water loss and solids uptake. Sodium alginate coating yielded significantly decreased solids uptake, without negatively affecting water removal. Overall, “dehydration efficiency” was drastically improved (up to 77%) by combined coating and counter-current contacting. Regression models were developed to predict mass exchange (i.e. water loss and solids uptake) under alternative treatment scenarios, considering initial product solids.