بررسي اثر آب گيري اسمزي با فشار كاهش يافته بر ميزان خروج آب و نفوذ ماده جامد در قارچ دكمه اي

The Effect of Reduced Pressure- Osmotic Dehydration on Water Loss and Solid Gain of Button Mushroom

Introduction: During the last few years, a large number of research projects have been conducted on optimization of drying process of mushroom slices to obtain high quality product with extended shelf life. One of the most useful pretreatments for drying is osmotic dehydration. The main advantage of this process is its influence on the principal drying method, shortening of the drying process, resulting in lower energy requirements. Considering that heat is not applied in this stage, osmotic dehydration offers higher retention of initial food characteristics, such as colour, aroma, nutritional constituents, and flavor compounds. The combination of pulsed vacuum osmotic dehydration (PVOD) and microwave drying of mushroom slices has been studied. Materials and Methods: The effects of some variables such as temperature (30-50°C), osmotic solution (brine 5-15%), contact time (60-180 min), vacuum pressure (500-700mbar) on water loss and solid gain in osmotic dehydration of sliced button mushroom were studied. The osmotic dehydration carried out on the reduced pressure and optimization of dehydration process was done by response surface methodology with central composite design. Results: The analysis of variance showed that a linear model predicted well the experimental data. The applied pressure had the main effect on water loss and solid gain. Optimization conditions were based on the higher water loss and lower solid gain. Conclusion: Optimal conditions were 46°C for osmotic temperature, 7% for salt concentration, 85 min for osmotic time and 638.69 mbar for pressure system.