Water sorption isotherms of vegetable seeds as influenced by seed species and storage temperature
Abdullah A. Alsadon
J. of Agric. Sci. 2001. Vol.23(2): 157-170.
2001
บทคัดย่อ
The water sorption isotherms of seeds of four vegetable species; carrot cucumber, and tomato were determined using the static method of eight saturated salt solutions (relative humidity range from 11 to 98% at four storage temperatures; 5, 15, 25 and 35 0C. The water sorption isotherms of each crop exhibited a reverse sigmoid shape. When seeds were stored at low relative humidity (RH), their equilibrium moisture contents (EMC) were relatively low. At 5 0C, no major changes in moisture sorption up to 80% RH. Beyond this point, a sharp increase in EMC occurred. In general, the increase in storage temperature incresed the water activity (aw) of seeds. At 97% RH, seeds held at 25 and 35 0C deteriorated before reaching equilibrium. The experimental data were fitted well with GAB and Henderson equations. Equilibrium moisture content varied from a minimum of 0.00236 (g water/g dry matter) from tomato to a maximum of 0.0388 for carrot. The correlation coeficient (0.968 to 0.999 for GAB model and 0.922 to 0.961 for Henderson model) indicated a good fit to experimental data. The GAB model fits experimental data better than Henderson model as indicated by the higher correlation coefficient value.