In this study, the reaction rates of native degerminated maize, extruded degerminated maize and enzymatically extruded degerminated maize using glucoamylase were evaluated and the extrudate models were investigated. The effects of enzyme concentration, substrate pH, temperature and incubation time on the reaction rates were studied. The Lineweaver–Burk equation was used in order to obtain the parameters of the kinetics equation of catalysed hydrolysis. The results show that NDM’s vm is 0.0845g/(mL·min) and km is 0.0032, EDM’s vm is 0.6251g/(mL·min) and km is 0.0167, EEDM’s vm is 1.897g/(mL·min) and km is 0.0240. The reaction rate of EEDM is quicker than those of NDM and EDM. The kinetics equation of EEDM is in accordance with the Michaelis–Menten equation.