Extraction of protein by 70 ethanol or water during dough-based refining of wheat flour

摘要

Technical, fluid-based separation of wheat starch and protein leads to selective extraction of components that alters the composition of the resulting protein and starch fractions. This study was conducted to identify protein compositional changes byhigh-performance capillary electrophoresis applied to fluids and solids obtained in and during the technical separation. Dough-ball and batter-like methods were applied using a Glutomatic or a McDuffie mixer and a vibratory screen. Fluids were water at 22 or 70% ethanol in water at 13. Data were referenced to extraction of wet, developed dough using 70% ethanol in water at 22 in the Glutomatic. The dough released starch immediately to either water or ethanol solutions. Water-soluble albumin proteins were released immediately to water, but the albumin and gliadin proteins generally appeared only after full displacement of the starch when ethanol was used regardless of the mechanical method. More gliadin was observed at earlier stages of extraction whenthe batter method was applied. Albumins not appearing as soluble in 70% ethanol were found associated with the insoluble crude starch. The slowly appearing gliadin proteins were released to the ethanol by random processes. These results suggest that cold-ethanol processing to produce crude protein and starch is dependent on the mechanical working of the dough in the presence of ethanol.