Investigation of osmotic dehydration parameters of plum (Prunus domestica) and theirs? effect on drying

In this study, osmotic dehydration parameters and theirs? effect on drying of yellow, red and Mürdüm plum were investigated. For this aim, effect of experimental parameters such as osmotic solutions, solution concentration, temperature, sample/solution ratio and pre-treatment application on osmotic dehydration and shrinkage of plum were studied. The effective diffusivities values for the water loss and solid gain occurring during osmotic dehydration were calculated with and without shrinkage.In order to investigate effect of osmotic dehydration on drying of plums which were with and without pre-treatment were studied after a day of osmotic dehydration application. Effective diffusion coefficients of plums during drying were calculated with and without shrinkage.Maximum dehydration of the plums was obtained in sucrose solution and pre-treatment application was showed different effects for different plums types and for each osmotic dehydration medium. The values of diffusion coefficients and water loss from plums were increase with both increasing in osmotic dehydration solutions concentration, osmotic dehydration medium temperature and decreasing in the sample/solution ratio.Shrinkage in diameter of the plums, osmotic dehydrated with and without pretreatment, were obtained between in the range of 33%-53%, 22%-84% respectively. The effects of different temperature application, osmotic dehydration solution concentration and the sample/solution ratio on diameter shrinkage of the plums were occurred as 16%-29%, 29%-40% and 18%-63%, respectively.The mechanism, controlled water transfer from plums, was found as diffusion inside of solid in drying process, applied after osmotic dehydration. Lower diffusion coefficients were calculated in case of shrinkage, taken into consideration for both osmotic dehydration and drying of plums.Keywords: Plum, osmotic dehydration, drying, shrinkage, diffusion coefficient, waterloss, solid gain, pretreatment.