Impact of flour heat treatment on cake batters

CHESTERTON, AMY K. S.; MEZA, BARBARA ERICA; SADD, PETER A.; MOGGRIDGE, GEOFF D.; WILSON, D. IAN

Atenas

Congreso; International Congress on Engineering and Food 11 (ICEF11); 2011

Commercial manufacture of high ratio cakes employs flours which have been subjected to heat treatment in order to improve their baking performance. Since the cake microstructure is directly dependent on the batter from which it is baked, the impact of heat treatment on batter rheology was investigated. Rheological testing (steady and oscillatory shear) was performed on batters made from heat-treated and untreated flours: (i) before, (ii) after the aeration stage, and (iii) after the final addition of fat. The maximum shear rates experienced during preparation were estimated for two commercial planetary mixers, a Kenwood KM250 and a Hobart N50-110, as 20-100 s-1 and 100-500 s-1, respectively. Rheological testing was complicated above 20 s-1 by normal force effects arising from the elasticity of entrained bubbles. Viscoelastic investigations showed that G">G´ in most cases. Frequency dependency data for the aerated emulsions at different temperatures (80, 90 and 100 C) were fitted to the weak gel model for foods. the AF values increased with temperature, indicating an increase in the strength of interactions in the gel. AF values at 90 and 100 C for aerated emulsions made with heat-treated flour and mixed for 6 and 10 min were higher than values obtained for samples made with base flour, indicating a stronger gel network in these materials. The results highlight the visco-elastic behaviour of cake batters under mixing conditions, and identify a method for quantifying differences between heat-treated and untreated flours.