The bread baking quality of six wheat starches differing in composition and physical properties

Starch was isolated from six types of wheat and separated into large A‐granule and small B‐granule fractions which exhibited a suitable range of properties. Respective amylose contents were 28.6–31.0% and 25.1–31.5%, lysophospholipids 707–1014mg 100 g −1 , and 1058–1398 mg 100 g −1 , and gelatinisation temperatures (GT) by differential scanning calorimetry (DSC) 58.4–62.7°C and 60.5–64.5°C. The A‐ and B‐granule fractions were remixed in various proportions and reconstituted with freeze‐dried gluten and freeze‐dried water‐solubles from flour to test the effects of changes in the properties of the total starch, A‐granule or B‐granule fractions, and the effects of various proportions of B‐granules on the quality of bread. The specific volumes of the loaves were not affected by starch amylose or lipid content, but were significantly correlated with either the GT of the total starches or their A‐granules. The optimum proportion of B‐granules was 25–35% by weight, but their GT had no effect on loaf specific volume. Staling changes were quantified from crumb compressibility measurements and the enthalpy of the endotherm for gelatinisation of retrograded amylopectin in stored breadcrumb, measured by DSC. Initial and limiting moduli of crumb firmness were correlated with loaf specific volume and starch GT, but rate and time constants calculated from the Avrami equation were independent. Rate and time constants and limiting enthalpy values calculated from the DSC results were independent of all other measured parameters.