|
Internal mass transfer during osmotic dehydration of gingers in sugar solution was examined as a function of concentration, temperature and immersion time of those solutions using moisture loss, sugar gain, molality and rate parameter. Influence of osmotic dehydration on browning reaction and texture properties of air dried rehydrated was also evaluated. Increasing the concentration and temperature of sugar solutions increased moisture loss, sugar gain, molality and rate parameter. Water loss and sugar gain were rapid in the first 3 min and then changed gentle slope. Moisture loss during osmotic dehydration using a sugar solution (60 Brix, 80℃) with 18 min immersion time was 40.05 g moisture/100 g wet ginger which was 52% reduction of initial moisture content in ginger (83.02%, wet basis). The changes of rate parameter were more affected by temperature than by concentration of sugar solution. Minimum browning degree (O.D.=0.027) was carried out by osmotic dehydration in sugar solution (40 or 50 Brix, 80℃) with 15 min immersion time compared to control (O.D.=0.132). Influence of osmotic dehydration on puncture forces of 3 min rehydrated ginger in boiling water were 22∼34% of reduction, while blanching treatment had not affected compared to those of control.
|