Cereal Chem 44:499 - 511.  |  VIEW ARTICLE
The Proteolytic Enzymes of Wheat and Flour and Their Effect on Bread Quality in the United Kingdom.

J. Hanford. Copyright 1967 by the American Association of Cereal Chemists, Inc. 

Proteolytic activity was measured by following the rate at which a gluten ball softened when incubated in water at 30 C., and by variations on the Ayre-Anderson method, in which a number of ways of determining soluble nitrogen were investigated. The indanetrione hydrate method was finally chosen for use. Both techniques were used to determine the proteolytic activity of native wheat flours and proteinase preparations. There was no correlation between the softening of the gluten of different wheat flours and the increase in soluble nitrogen as measured by a modified Ayre-Anderson method. Total soluble nitrogen showed a correlation with the nitrogen supplementation requirements of flour doughs. The softening enzyme was affected by the flour grade and was inhibited when the gluten was washed with dilute sodium chloride solution. The Ayre-Anderson test was not a satisfactory method of measuring this enzyme. A concept of alpha- and beta-proteinases is proposed to explain these results, the gluten-softening enzyme being termed alpha-proteinase and the soluble nitrogen-producing enzyme, beta-proteinase.