ABSTRACT
The drying consisted of plant exposure to solar light. This procedure was conducted until the seeds reached a moisture content of approximately 6% wet basis. The equilibrium moisture contents were determined, by the statistic method using sulfuric acid solutions with 98% purity for a relative humidity varying from 17 to 85%. The samples were placed in wire baskets and stored in hermetic bottles containing the respective solution, and placed inside the incubator with the temperature controlled at 20, 30 and 40º C ± 1º C. For the sorption isotherms adjustments, the BET, GAB, Halsey and Oswin models were tested in order to obtain the coefficients of these equations by non-linear regression analysis. According to the results, it may be concluded that the seeds need 35 days to reach the moisture content equal to 6.1% wet basis and the GAB model showed best adjustment for the experimental data.
Key words:
natural drying; hygroscopic equilibrium; seeds; Sesamum indicum