Correlations of the Amount of Gluten Protein Types to the Technological Properties of Wheat Flours Determined on a Micro-scale

Abstract

Flour samples of 14 wheat cultivars previously characterised by rheological measurements and by baking tests on a micro-scale (Kieffer et al.: Journal of Cereal Science27 (1998) 53–60) were analysed for the relative amounts of gluten protein types using a combined extraction/HPLC procedure. Regression analysis was used to find relations between wheat properties and protein quantities. The results indicated that the maximum resistance of dough and gluten and the gluten index were strongly dependent on the quantity of glutenin subunits (GS) in flour; additionally they were influenced by the ratio of gliadin to glutenin subunits. Within the family of glutenin proteins, the correlation coefficients for high-molecular-weight (HMW) and low-molecular-weight (LMW) GS were in a similar range, but twice the amount of LMW GS was necessary to get the same resistance as with HMW GS. Among HMW GS, the contribution of x-type GS was more important than those of y-type GS. The extensibility of dough and gluten was mainly dependent on the ratio of gliadin to total glutenin subunits, to HMW GS and LMW GS. Dough development time showed the highest correlation with total HMW GS and x-type HMW GS. Bread volume was influenced by the total amount of gluten protein more than by the amount of protein in different groups or of different types, probably because of the rather low range of flour protein content (8·7–12·0 %) within the set studied. Significant differences between gliadins and glutenins with respect to their effects on bread volume could not be detected. The correlation between bread volumes and the quantity of gluten proteins was higher, when dough was mixed to optimum.