Journal of Crop Production and Processing

In this study the effect of different levels of moisture content of maize grits (10, 13, 16 and 19%) as an attribute of physicochemical properties of extruder-derived puffed products, was investigated. The results showed that with increasing maize grits' moisture content, water absorption index (WAI) and water solubility index (WSI) were decreased. Moreover, with changing in feed moisture content from 10 to 16%, the volume and sectional expansion index (SEI) increased but further increase of moisture content to 19% caused a reduction in these parameters. The textural tests also revealed that with increase in moisture content, the compression energy (Nmm), maximum force (N) and time to achieve the first major peak (s) were increased but the number of peaks was decreased. With increase in the moisture content, specific mechanical energy (SME) was decreased, due probably to the reduction in the viscosity of melt. With increase in the moisture content the L and b values were increased but the value of the samples were decreased due to the reduction of Maillard reaction rate. Our data confirms that the moisture content of maize grits may play an important role in the quality of produced extruded snacks and a high quality product can be achieved by optimizing this parameter. In this research, the maximum volume of the extruder product was obtained in 16% of moisture level.