Study on Processing and Modeling of Onion by Drying

Abstract

A drying process of fresh onion has been studied, The experiments have been
carried out to examine the effect of pretreatment with some chemicals and drymg
temperature on quality of dried onion as well as the optimum condition for storage. Fresh onion is soaked in sulfur dioxide and ascobic acid solution prior to drying
ill cabinet tray dryer at 5QoC, 60°C and 70°C. The results are well fit to exponential
equation with only one constant variable.The results also showed the samples drying at
higher temperature have higher drying rate as compare with the samples driedat lower
temperature. However, the quality of sample treated with sulfur dioxide solution and dried
at lower temperature of 50°C is much better than those dried at higher temperature.
Moreover, the pretreatment prior to drying and the temperature of drying process have no
Significant effect on drying and rehydration ratio.