Cereal Chem 46:242 - 252.  |  VIEW ARTICLE
Effect of Moisture Content on Mechanical Properties of Shelled Corn.

L. Shelef and N. N. Mohsenin. Copyright 1969 by the American Association of Cereal Chemists, Inc. 

The effect of moisture content on mechanical properties of yellow dent corn was studied by applying uniaxial compression to individual kernels. Before testing, kernels were equilibrated at each of several relative humidity atmospheres to give a range in moisture contents of 6.53 to 28.00%. In addition, one sample was dried in a vacuum oven to a residual moisture level of 0.74%. The Instron testing machine was used, and loading was either by cylindrical indenter, parallel plates, or spherical indenter. Three moisture- dependent parameters were evaluated from load-deformation relations obtained at different loading levels: (a) the linear limit load, up to which the load-deformation relation was linear; (b) the apparent modulus of elasticity; and (c) the modulus of deformability. Each of these parameters decreased with increase in moisture content of the kernel. Under the testing conditions employed, the major contributor to the mechanical properties observed was the horny endosperm; at low moisture levels this was very stiff. Increasing moisture content reduced the friction coefficient of the system and caused deformations to increase and moduli to decrease as pressure was applied. Results from the tests on the floury endosperm indicated considerably lower values for the three parameters evaluated but were not consistent.