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Physical and Milling Characteristics of Wheat Kernels After Enzyme and Acid Treatments¹

¹Contribution No. 08-22-J from the Kansas Agricultural Experiment Station. Mention of any company name or product does not constitute endorsement by Kansas State University or the Grain Science and Industry Department. ²Research assistant professor, graduate research assistant, and professors, Grain Science & Industry Dept, Kansas State University, Manhattan, KS 66506. ³Corresponding author. Phone: (785) 532-2875. Fax: (785) 532-7010. E-mail: lamsal@ksu.edu

The current wheat milling process separates bran from endosperm by passing tempered wheat kernels through successive break rolls and sifters. Using hydrolytic enzymes during tempering degrades bran and aleurone layers and can improve milling efficiency and yield. This study was conducted to evaluate the effects of chemical and enzymatic treatments of wheat kernels before milling on physical and milling characteristics of the resulting wheat and flour quality. Hard wheat kernels were soaked in dilute acid or water and dried back to original moisture before being tempered with enzymes in water. Kernel physical and milling characteristics (600 g) were evaluated. Dilute acid soaking did not affect the 1,000-kernel weight and diameter but softened treated kernels. When treated kernels were pearled, bran removal was mostly from ends; and the reducing sugar content in enzyme-treated bran was significantly higher than the control. Compared with the control, acid-soaked enzyme-tempered kernels showed small but significant improvement in straight flour yield, with virtually no difference in protein content, and flour color. Chemical and enzyme treatment resulted in higher ash in flour. These differences were not seen in milling of larger batches (1,500 g) of kernels.