پيش تيمار هويچ خشك شده با هواي گرم بوسيله آبگيري اسمزي

Osmotic dehydration pretreatment for air-dried carrot

Osmotic dehydration, the process for partial water elimination from food stuffs. that is called partial drying.involves product immersion in a hypertonic aqueo us so lution.The process has been used mostly as a pretreatment before di fferent drying methods Such as : Hot air-drying.Vaccum drying, Free ze drying, Microwave drying, .. ..there fore, osmoti c dehydration process was used as a pretreatment before air drying of carrot ,For identification of optimum operating conditions, several factors such as solution concentration, its temperature.contact time and the rate of salt and gluco se gains in carrot texture were investigatedTemperature treatments inc!uding:25,4O,55 °c and time treatments were 15.30.60,120,240 and 360 minutes. Three levels of glucose syrup (30 ,40 and 50%) and three level s of sodium chloride (5,10 and l5%) were used to provide nine different solutions.The optimum operating co nditions in view of wate r loss and solid gain were at 40°C fo r 240 minute.The res ults showed that the glucose and salt solution of the conce ntratio n 50% + 5%, respec tively, that was the best co ncentration have a smaller solid gain (SG) and large water Joss(WL).