Milling quality and rheological properties of two selected local and newly introduced rice cultivars; impacted by drying parameters and milling system

Abstract

Various postharvest parameters have an impact on the milling quality and rheological properties of rice. The objective of this study was to appraise the whole rice kernel percentage and pasting properties of local and newly introduced rice cultivars as affected by drying air temperature, grain final moisture content and type of rice whitener. The results of whole kernel percentage (WKP) indicated the superiority of abrasive type whitener over the friction type whitener. Bending strength had significant negative correlation with chalkiness, length, width and length to width ratio of grain. There was no significant correlation between WKP and bending strength. For Gohar, results showed that the drying parameters and type of whitener has a significant effect on final, breakdown, and setback viscosity. These differences, however, were not significant for Hashemi. Furthermore, the highest level of the breakdown viscosity and final viscosity was observed for severe drying accompanied with friction type whitener, while the lowest level of final viscosity was belonged to low temperature drying and abrasive type whitener. So drying parameters and milling system can be effect on milling quality and rheological properties of some rice cultivars.