Milling properties of peas in relation to texture analysis. Part I. Effect of moisture content Original Research Article

A new efficient method to evaluate the milling behaviour of peas in a classifier hit mill has been developed. The energy uptake to split a pea in a texture analyser with a Stanley knife set-up was compared with energy uptake of pea in a classifier hit mill as function of moisture content. Drier peas showed a less elastic and ductile behaviour in the texture analyser and were found to be harder than wet peas. However, the increase of brittleness at lower moisture contents decreases the total energy uptake to create a fracture. The same energy decrease was found for the milling experiments and peas with lower moisture contents needed less energy to create new surfaces in a hit mill. The total energy uptake in the mill was higher than in the texture analyser, but of the same order of magnitude and with the same relation with the moisture content. Small deviations from the linear correlation between energy uptake of the texture analyser and the classifier hit mill could be explained by the difference in the deformation rate during breaking. Consequently, a lower milling speed showed a better correlation than a higher milling speed.