title: Biomechanical properties of wheat grains: the implications on milling.
abstract: Millennia of continuous innovation have driven ever increasing efficiency in the milling process. Mechanically characterizing wheat grains and discerning the structure and function of the wheat bran layers can contribute to continuing innovation. We present novel shear force and puncture force testing regimes to characterize different wheat grain cultivars. The forces endured by wheat grains during the milling process can be quantified, enabling us to measure the impact of commonly applied grain pretreatments, such as microwave heating, extended tempering, enzyme and hormone treatments on grains of different 'hardness'. Using these methods, we demonstrate the importance of short tempering phases prior to milling and identify ways in which our methods can detect differences in the maximum force, energy and breaking behaviours of hard and soft grain types. We also demonstrate for the first time, endosperm weakening in wheat, through hormone stratification on single bran layers. The modern milling process is highly refined, meaning that small, cultivar specific, adjustments can result in large increases in downstream profits. We believe that methods such as these, which enable rapid testing of milling pretreatments and material properties can help to drive an innovation process that has been core to our industrial efforts since prehistory.
authors.affiliation: School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK.
authors.forename: James E
authors.identifier: 0000-0002-4183-8673
authors.initials: JE
authors.lastname: Hourston
authors.affiliation: School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK.
authors.forename: Michael
authors.identifier: 0000-0003-3419-2074
authors.initials: M
authors.lastname: Ignatz
authors.affiliation: School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Reith
authors.affiliation: School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK.
authors.forename: Gerhard
authors.identifier: 0000-0002-6045-8713
authors.initials: G
authors.lastname: Leubner-Metzger
authors.affiliation: School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK tina.steinbrecher@rhul.ac.uk.
authors.forename: Tina
authors.identifier: 0000-0003-3282-6029
authors.initials: T
authors.lastname: Steinbrecher
mesh_terms: D002523:Edible Grain / Q000737:chemistry*; D005511:Food Handling; D008872:Microwaves; D013314:Stress, Mechanical; D014908:Triticum / Q000737:chemistry*
keywords: biomaterial characterization; milling; seed biomechanics; shear force; tissue weakening