Effect of osmotic pretreatment on quality of mango chips by explosion puffing drying

The effect of osmotic dehydration pretreatment duration (30, 60 and 120 min) on the glass transition, texture, color, expansion, rehydration and other properties of mango chips was investigated. Mango slices were immersed into 65 °Bx sucrose solution at 30 °C and then predried to a moisture content of 30 g water/100 g by hot-air-drying at 50 °C. The mango chips were then obtained by explosion puffing drying. The osmotic pretreatment improved the color of mango chips, whereas sucrose impregnation resulted in a hard and brittle texture. The non-pretreated samples had a higher glass transition temperature, expansion ratio and rehydration ratio and lower hardness and crispness values than the pretreated samples. With increasing immersion time, the glass transition temperature decreased and the water activity simultaneously increased for the chips. Sensory evaluation showed that the pretreated samples were of better overall quality than the non-pretreated samples, although this difference is slight.