2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

Previous research on rice processing has shown that high drying and tempering temperatures and high rates of moisture removal may be employed in drying rough rice without reducing milling quality. The objective of this work was to characterize flours and starches obtained from rough rice samples dried at different temperatures. Separate lots of rough rice samples from cultivars Bengal and Cypress were dried at 20, 40, and 60°C to a moisture content of about 12.0%. Flour and starch samples were prepared from milled, dried grains and evaluated for pasting characteristics with a Brabender viscoamylograph, thermal properties with a differential scanning calorimeter, and starch molecular-weight distribution with a high-performance size-exclusion chromatograph. Among the flour properties evaluated, only pasting characteristics were affected by both drying temperature and cultivar. Peak viscosity of rice flours increased with an increase in drying temperature, which was not observed for starch samples. The alkali-soluble material discarded in the isolation of starch may contribute to this trend in pasting properties. For the starch samples, variations in thermal, pasting and molecular weight distribution were mainly cultivar-related. The influence of drying temperature on starch properties was not evident.