AACC InternationalAACC International

Cereal Chemistry Home
Cereal Chem 52:146r - 153r.  |  VIEW ARTICLE
Hypothesis for the Structure of Glutenin in Relation to Rheological Properties of Gluten and Dough.

C. T. Greenwood and J. A. D. Ewart. Copyright 1975 by the American Association of Cereal Chemists, Inc. 

The suggested molecular unit of glutenin is the concatenation. This consists of a variable number of polypeptide chains, not necessarily of the same type, which are joined together by disulfide bonds to form a super-molecule possessing a linear (i.e., unbranched) configuration. Concatenations can adopt very complex conformations in water, and will often be entangled with one another. Regions of strong interaction and entanglement points (nodes) form the cross-links that are essential for rubber-like elasticity. Individual polypeptide chains in a concatenation may be unfolded by stress: the natural tendency of such chains to return to a compact state of lower free energy accounts for elasticity. Since nodes depend on secondary forces only, they are capable of being unraveled by stress. This process is merely a special case of molelcular slip, and it is the latter that accounts for viscous flow in gluten and dough. The model explains the sensitivity of dough and gluten to disulfide-bond breaking agents, since the probability of entanglement decreases rapidly as the average length of a concatenation falls. The tensile strength expected for such a system is of the order observed.

© Copyright AACC International  | Contact Us - Report a Bad Link