FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Impact of the concentration and temperature of starch syrup on the kinetics of osmotic dehydration of pumpkin


Osmotic dehydration allows to partially remove water and to reduce water activity in the material without any phase change. This method is more and more commonly used in the fruit and vegetable industry owing to the fact that initial features of raw materials are well retained and economic benefits are achieved. Additionally, this method allows for preserving the product and for increasing its stability along with retaining, simultaneously, its high quality. The osmotic dehydration can be applied to initially preserve a pumpkin. Owing to its nutritive values, the popularity of pumpkin among consumers increases. The objective of this study was to explain the phenomena occurring during the pumpkin dehydration carried out in the solution of starch syrup used as an osmotic solution. The impact of the concentration of solution (20–66.3 %) and of the temperature (20–60 °C) on the kinetics of osmotic dehydration of pumpkin were determined. The process was conducted with the ratio of raw material and osmotic solution being 1:4, during a period of 0 – 300 min. After a definite period of dehydration time, the mass and dry matter losses were determined. In order to describe the process studied, the water content and water loss were determined as were the solid gain and the dehydration efficiency effectiveness. It was found that the concentration and temperature of starch syrup solution essentially impacted the kinetics of mass exchange during the osmotic dehydration of pumpkin. The higher the osmotic solution concentration and temperature of the process was, the higher efficiency of the process was. Particularly, the rise of temperature from 40 to 60 °C has significantly intensified the process of removing water from the pumpkin. The best results of the osmotic dehydration of pumpkin were achieved when a 66.3 % starch syrup solution was used at a temperature of 60 °C. However, when the process was performed at a temperature of 20 °C, the results obtained were less satisfactory.


osmotic dehydration, mass exchange, pumpkin