Combined Osmotic and Air Dehydration for the Production of Shelf-Stable White Cheese

The research targeted on the production of an innovative shelf-stable cheese of high quality, through the combinatory effect of osmotic dehydration (OD) as pretreatment and conventional air-drying. The optimum OD processing conditions (process time/temperature, concentration of osmotic solution, food to OD agent ratio) were determined through a kinetic study of the effect of OD parameters on the water activity (a(w)) and water/solid transport phenomena, organoleptic and quality characteristics of the white cheese in cubes. Through Fick's second law for mass transfer, water and solid diffusion coefficients were determined. Taking into consideration thea(w), the quality, and organoleptic characteristics of the final product, the optimum OD conditions were selected as 15 degrees C process temperature, food to osmotic agent ratio 1:4 (w/w), concentration of osmotic agent 65% to glycerol, and treatment time 30 min. The final moisture anda(w)of the OD-treated product were calculated as 40% and 0.88, respectively. The time of OD-pretreated product for air-drying at 40, 55, and 67 degrees C to 5% residual moisture was reduced by 35, 51, and 65% respectively. The selected air-drying conditions were 67 degrees C for 4 h. Quality parameters of the final white cheese product were studied during its storage at 15-40 degrees C, and the shelf life was estimated as 6 months at ambient temperature.