Soft wheat quality characteristics required for making baking powder biscuits

Fifteen soft wheat varieties were evaluated for their grain, milling, flour and dough mixing characteristics, as well as their solvent retention capacities (SRCs), pasting properties and suitability for making baking powder biscuits, to identify wheat quality characteristics required for making biscuits. Grain and flour protein contents and sodium dodecyl sulfate sedimentation (SDSS) volume showed positive relationships with biscuit height and shape factor (SF). Kernel hardness, damaged starch content and water SRC exhibited negative correlations with biscuit specific volume (SV), while peak viscosity and grain protein content were positively associated with biscuit SV. Stepwise multiple regression analysis indicated that biscuit height and SV can be predicted from flour protein content (R2 = 0.65) and damaged starch content (R2 = 0.69), respectively; while SDSS volume and flour yield together predict biscuit SF (R2 = 0.83). Cluster analysis based on biscuit height and SF indicated that seven soft wheat varieties with flour protein contents greater than 7.9% and SDSS volumes lower than 32.0 mL produce good-quality biscuits with high height, intermediate SF, great SV and soft crumb. The results of this study suggest that soft wheat flours with intermediate-to-high protein contents (7.9-9.7%), intermediate SDSS volumes (20.0-32.0 mL) and low damaged starch contents (1.9-3.4%) are suitable for making desirable-quality biscuits.