Thin-layer drying of some Sri Lankan paddy varieties under low humid conditions

Abstract

Thin-layer drying characteristics of paddy were examined within the relative humidity range from 30% to 60%. A test chamber has been constructed with Perspex and continuously flushed with low humid air to control the inside relative humidly at required levels and several homogeneous thin layer paddy samples were dried inside the chamber. BG 300, BG 352 and BG 357 paddy varieties developed by Rice Research and Development Institute, Bathalegoda, Sri Lanka have been used in this study. Normalized drying data was transformed into dimensionless parameter called Moisture Ratio, and fitted with four semi-theore tical models. Correlation coefficients, standard errors and residual plots were used as criteria for evaluating the goodnes s-of-fit. Of the models used the two-term exponential model was found to fit well with the experimental data and is recommended as the thin-layer drying model for paddy.