Submitted to: American Association of Cereal Chemists Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 11/9/2000
Publication Date: N/A
Technical Abstract: The effect of processing conditions in an excess steam jet cooker on the degradation of waxy maize starch was studied. The temperature of the steam, the ratio of the flow rate of the starch slurry to the steam flow rate, and the concentration of starch were determined to influence the extent of degradation. The viscosity of concentrated solutions of the jet-cooked product and the intrinsic viscosity of dilute solutions were used as measures of the extent of molecular degradation. The viscosity decreased at higher reaction temperatures, and for higher steam to starch ratios. Multiple passes through the jet cooker decreased the viscosity dramatically for the first two passes, but little additional effect was observed for further passes. The residence time in the reactor had little effect on the viscosity. The results suggest that the degradation mechanism for waxy maize starch in a jet cooker is primarily thermal degradation. These results are useful both for controlling the product viscosity and for scaling of the jet-cooking process.