The sorption isotherms of maize meal

Abstract
Summary. The equilibrium moisture contents of the three main grades of South African maize meal over a range of 1.4‐90.7% relative humidity (r.h.) were determined at 30°C. It was found that the fat content of maize meal influenced the moisture content at equilibrium, i.e. the higher the fat content, the lower the equilibrium moisture content for a specific relative humidity. Both desorption and adsorption isotherms for maize meal were found to be sigmoid and the effects of hysteresis were encountered in all cases. On prolonged storage mould growth occurred in maize meals held in an atmosphere of 84% r.h. and higher. From the sorption isotherms the maximum r.h. at which maize meal could be stored without the danger of mould contamination could be predicted.