Abstract
Raw okara (soy pulp), a by-product from tofu manufacturing, having a water content of approximately 70% could be easily dried and roasted by heating in an oven in a temperature range of 80-180°C. Roasting reduced the weight of raw okara by more than its water content. The water absorption rate of okara was decreased by roasting, the rate of this decrease increasing with the temperature and duration of roasting. Roasting also reduced the protein content and altered the protein composition. Native-PAGE and SDS-PAGE results suggested that the proteins in okara were denatured or degraded by roasting, resulting in the dissociation of complexes, breakdown of higher-order structures, and changes in properties like solubility, thus ultimately leading to a reduction in the overall water absorption rate. Roasted okara added at 10% to bread dough promoted gluten formation and improved leavening of the bread. The Properties of okara induced by roasting are thought to be effective for this improvement in the leavening process.
