Cereal Chem 44:324 - 332.  |  VIEW ARTICLE
Protein Alteration in Flour Damaged by Ball-Milling and Roller-Milling.

B. L. D'Appolonia and K. A. Gilles. Copyright 1967 by the American Association of Cereal Chemists, Inc. 

Protein alteration in flour milled with varying degrees of severity by ball and roller mills was studied by means of nonprotein nitrogen (NPN) determinations, specific color reactions, Sephadex column chromatography, gel electrophoresis, and sulfhydryl group analysis. The proteins of the water-soluble fraction were studied most extensively. The possibility of protein denaturation in highly damaged flour was indicated by a decrease in the total flour nitrogen contained in the water-soluble fraction. An increase in NPN in the water-solubles was observed as severity of milling increased. Two color reactions for measurement of amino groups supported the NPN results. In addition, the water-soluble proteins produced two main peaks when separated on a Sephadex G-50 solumn. Average values for several column determinations indicated a slight increase in the lower-molecular-weight protein content of the damaged flour. These data indicate an alteration of the protein structure. Gel electrophoresis of water-soluble proteins revealed 12 components with no extreme differences between undamaged and damaged samples. Likewise, the -SH content did not show appreciable quantitative differences.