Date of Award

1985

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

Rice flour was modified with either 0.1, 1.0 and 5.0% acetic or succinic anhydride for 1, 6 and 18 hr under basic conditions. The pH was maintained above 7.0 using either sodium hydroxide or sodium carbonate. The results showed that modified rice flours had lower fat content as compared with the unmodified rice flour (control). The type of anhydride significantly influenced the fat content of rice flour. Ash content of rice flour increased significantly due to the anhydride concentrations and alkali type. Significant differences were also found in the protein content of modified rice flours due to the use of anhydride and alkali types. Different concentrations of anhydrides alkali types resulted in an increase in the total color and chromaticity differences from the control. In general, solutions of modified rice flour had better clarity than that of the control. Flour slurries behavior under neutral and acidic conditions was altered by modification with the anhydrides. Significant differences were found among the peak viscosities at 95(DEGREES)C, viscosities after holding at 95(DEGREES)C for 30 minutes and the setback viscosity of modified rice flours. Flour modification resulted in production of rice bread with better quality and acceptability when compared with bread produced with unmodified rice flour. Breads with larger volume, softer crumb and better taste were produced from modified rice flour. Although some modifications resulted in inferior quality breads. Electron micrographs of rice flour and rice breads revealed that modification with anhydrides influenced their ultrastructure noticeably in comparison with that of unmodified rice flour and bread.

Pages

208

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