The impact of rum on physicochemical properties of sorghum and wheat pound cakes

Sorghum, a sustainable, gluten-free grain, typically results in baked goods with decreased volume, decreased crumb flexibility, and undesirable texture. The purpose of this study was to investigate the effect of ethanol, added as rum, on the physicochemical properties of sorghum and wheat-based pound cakes. A 2 × 2 factorial design was used to compare pound cake formulations: sorghum with rum (SR), sorghum without rum (SN), wheat with rum (WR), and wheat without rum (WN). For both base flours, rum was added at 31% flour basis, replacing water (194 mmol ethanol/100 g flour). Data were collected on batter specific gravity, batter temperature, and baked product weight, volume, internal structure, and texture. Rum contributed to increased batter aeration, as measured by specific gravity decrease from 0.902 to 0.831 (sorghum) and 0.950 to 0.869 (wheat). Product volume was decreased by rum addition for both base flours, attributed to delayed or inadequate structure-setting. Rum increased the hardness of both cakes, however the impact of internal structure was different for both base flours. Wheat cakes had higher residual ethanol after baking, as compared to sorghum, despite higher structural porosity and non-significant differences in bake loss between both treatments. Overall, the results indicate that ethanol at 194 mmol/100 g flour in a pound cake formula is detrimental to starch and protein transformations associated with desired end-product characteristics, with differing impact in wheat and sorghum-based formulas.