Application of osmotic treatment in tomato processing—effect of skin treatments on mass transfer in osmotic dehydration of tomatoes

Abstract

Osmotic dehydration can be a method to minimize negative modifications of fresh food components during processing. Cut tomatoes are poorly suited to osmotic dehydration because of their heterogeneous texture and potential excessive loss of liquid components. Moreover, the limiting stage of whole tomato fruit dehydration is water movement through the skin. Skin treatments followed by osmotic dehydration of whole tomatoes was tested. A NaOH solution mixed with ethyl oleate had less tomato fruit peel damage and higher water removal, than a NaOH solution by itself. The NaOH solution was more effective than a HCl solution in water removal. Chemical skin treatment of 7–8% NaOH solution resulted in undesirable tomato texture softening at room temperature. Physical skin puncturing treatment had higher water removal potential than chemical skin treatments. Physical treatment of tomato skin did not create waste material. A kinetic study was done to analyze the relationship between skin permeability and the mass transfer property.