Effect of fermentation with Rhizopus oligosporus on some physico-chemical properties of starch extracts from soybean flour

Studies were carried out on the changes that occurred on some selected physico-chemical properties of starch extracts from soybean flour when fermented with Rhizopus oligosporus. This was done in order to increase the utilization potentials of the flour. Starch extracts were obtained from flour obtained from fermented soybean using R oligosporus with a fermentation period of between 0 and 72 h. Some physicochemical properties, as well as the amylose, amylopectin, and the pasting characteristics of the starch extracts were determined using standard methods. Increasing trends with increasing fermentation period were observed with respect to most of the physico-chemical characteristics investigated, except for the reconstitution index that showed decreasing trends. While the peak breakdown and final viscosities also decreased, the swelling power and solubility slightly increased with increase in fermentation period. The proportion of amylopectin which was constantly high showed further slight increases with fermentation, apparently because of the decreasing proportion of amylose probably due to utilization by the mould X oligosporus used for fermentation. (C) 2009 Elsevier Ltd. All rights reserved.