Effects of Different Concentrations of Sucrose Solution on Quantitative and Qualitative Properties of Osmo-dehydrated Pear Slices by Reconstituted Osmotic Solutions

Food dehydration process in several reasons, causes deteriorate qualitative characteristics in final products. It is necessary to use some pretreatments such as osmotic dehydration. In this research, during osmotic dehydration of pear rings, the effects of concentration of sucrose solutions of 50 and 60 percent (w/w), in constant temperature of 30ºC, and reconstitution of osmotic solutions (until 5 times), were investigated on quantitative and qualitative characteristics of osmotic samples, such as pH, hardness, color of texture, total sugar and moisture content of osmotic samples and pH, turbidity, viscosity of solution osmotic. The result showed that with increase concentration osmotic solution and reconstitution of osmotic solutions pH of sample and solution is increase and decrease respectively. It’s because of increase the moisture content and extraction acids from texture of osmotic sample. Also reconstitutions of osmotic solutions will cause increase the turbidity in solution, that reason is increase the production of pigment in solution. Also increases the density of osmotic solutions may cause increase the color of osmotic samples and we can say that the reason is extraction of colorful compound from texture of sample. The most reason of hardness of texture is related to a sample that it processed in a solution that is 5 times concentrated. Finally the coated sample that was osmotic dehydrated and fifth reconstituted solution was known as the superior sample.