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Influence of Starch and Gluten Characteristics on Rheological Properties of Wheat Flour Gel at Small and Large Deformation

¹National Food Research Institute, Kannondai, Tsukuba, Ibaraki 305-8642, Japan. ²Corresponding author. Fax: +81-29-838-7996. Phone: +81-29-838-8031. E-mail: tomokos@affrc.go.jp ³National Agricultural Research Center for Western Region, Nishifukatsucho, Fukuyama, Hiroshima 721-8514, Japan.

Starch and gluten were isolated from 10 wheat cultivars or lines with varied amylose content. The rheological properties of 30% wheat flour gel, starch gel, and the gel of isolated gluten mixed with common starch were determined in dynamic mechanical testing under shear deformation, creep-recovery, and compression tests under uniaxial compression. Variation of wheat samples measured as storage shear modulus (G′), loss shear modulus (G″), and loss tangent (tan δ = G″/G′) was similar between flour and starch gels and correlated significantly between flour and starch gel. The proportion of acetic acid soluble glutenin exhibited a significant relationship with tan δ of gluten-starch mixture gel. The small difference in amylose content strongly affected the rheological parameters of flour gels in creep-recovery measurement. Wheat flour gel with lower amylose content showed higher creep and recovery compliance that corresponded to the trend in starch gel. Compressive force of flour gel at 50 and 95% strain correlated significantly with that of starch gel. Gel mixed with the isolated gluten from waxy wheat lines appeared to have a weaker gel structure in dynamic viscoelasticity, creep-recovery, and compression tests. Starch properties of were primarily responsible for rheological changes in wheat flour gel.