Abstract
The addition of 10% w/w cocoa powder to wheat flour decreased the loaf volume of the bread, while the addition of a cocoa hot-water extract (CHWE) increased the loaf volume. The components of the distilled water fraction and 20% ethanol fraction of CHWE, which contained a substantial amount of polyphenolic substances, were particularly effective in increasing the loaf volume. Polyphenol-free CHWE-added bread had a similar volume to that of standard bread. The gas production during fermentation was almost the same with or without adding CHWE. Optical and transmission electron micrographs showed that the gluten network of the CHWE-added dough after fermentation was well developed, the gluten matrix including many air spaces. Brabender tests showed that the CHWE-added dough had a higher consistency and greater dough strength than standard dough, and that the maximum viscosity of the starch was markedly higher. It is concluded that the increase in loaf volume of CHWE-added bread resulted from changes in the properties of the gluten matrix and starch granules in the dough.
