In situ measurement of the rheological properties of wheat and barley grain using the SKCS 4100.

ABSTRACT The phenomenology of wheat hardness can be characterized in terms of different forms of rheological measurements and interpretations, and related to key processing performance properties. Most of this knowledge has been obtained through laborious measurements of the mechanical properties of small samples taken from the botanical layers of wheat. Recently, measurements performed on the SKCS 4100 instrument of the crushing of individual whole grains has allowed the rheological information to be recovered in situ. By applying averaging to the data collected of the crushing performed by the SKCS 4100 on a number of individual whole grains representative crush-response profiles (CRPs) can be generated. The rheological phases of the crushing of whole grains can be recovered from their CRPs and related directly to the responses of its individual botanical layers to the crushing. These responses include: 1. Elastic response of the aleurone layer 2. Collapse of the shell into the internal porosity 3. Viscoelastic response of the compressed endosperm Such measurements have established that wheat CRPs have a common generic structure, but those for barley can be separated into several Equivalence Classes, in increasing order of geometric complexity of their structure between the shell collapse and the start of the endosperm response.