A compositional breakage equation for wheat milling

Abstract

The compositional breakage equation is derived, in which the distributions of botanical components following milling of wheat are defined in terms of compositional breakage functions and concentration functions. The forms of the underlying functions are determined using experimental data for Outer Pericarp, Intermediate Layer, Aleurone and Starchy Endosperm generated from spectroscopic analysis of milled fractions of a hard and a soft wheat milled under Sharp-to-Sharp (S-S) and Dull-to-Dull (D-D) dispositions. For the hard Mallacca wheat, the Outer Pericarp, Intermediate Layer and Aleurone compositions mostly varied with particle size in similar ways, consistent with these layers fusing together as "bran" and breaking together, although with possibly a subtle difference around the production of very fine particles under D-D milling. By contrast, for the soft Consort wheat, Outer Pericarp, Intermediate Layer and Aleurone were distributed in broken particles very differently, particularly under D-D milling, suggesting a different breakage mechanism associated with differences in the mechanical properties and adhesion of the bran layers. These new insights into the nature of wheat breakage and the contributions of the component tissues could have implications for wheat breeding and flour mill operation.

Examination of milling technological properties of different wheat varieties

“…The soft variety, GK F eny produces much larger bran particles compared to the hard variety. This finding confirmed the consequences of Galindez-Najera et al (2016).…”

“…In milling technology, the degree of kernel hardness is proportional to the energy used for grinding, since the grinding of harder kernel requires far more energy than soft ones. The broken particles distribute differently in hard and soft cultivars (Galindez-Najera et al, 2016). In addition, the kernel hardness specifies the conditioning parameters, the flour particle size, the density, the starch damage rate and through this the flour water absorption ability and the flour extraction rate.…”

“…With regard to requirements for final use, several types of grinder can be used: roller, disk, stone, and hammer mill (Farkas, 1977). The reason why mills use roller mill is the separating mechanism of breakage, where the endosperm fragments in small particles (100-200 mm), the bran fragments in the large particles, like pericarp, and aleurone (2,000-2,100 mm) (Fistes & Tanovic, 2006;Galindez-Najera et al, 2016). During our experiment two different grain structured varieties of wheat (soft and hard) were milled in laboratory conditions with disk, stone, and a roller grinder in air-dry and conditioned circumstances.…”

Application of response surface methodology for optimization of wheat flour milling process

“…Previous studies have modeled particle size distribution throughout the mill grinding and separation process (Campbell, Bunn, et al, 2001;Campbell et al, 2007;Fang & Campbell, 2003;Galindez-Najera et al, 2016). These results demonstrated that the particle size distribution was impacted by conditioning level and roll gaps in the break system along with other factors such as grain size and hardness.…”

Particle size distribution control during wheat milling: nutritional quality and functional basis of flour products—a comprehensive review

“…They further extended the dataset for this model (Fuh et al, 2014). Galindez-Najera et al (2016) further demonstrated that the continuous crushing function can also be defined as a crushing function related to particle composition for predicting particle size distribution. The experimental data they generated enriched the practical implications of this theory.…”