Effect of processing on the chemical qualities and functional properties of soy flour

Soybean (Glycine max) seed varieties, SAMSOY 1, SAMSOY 2 and TG X 536-02, were each processed into five flour batches by fermentation, germination, cooking, autoclaving and processing raw. The proximate minerals compositions and functional properties of the prepared flours were evaluated. Raw soyflour contained 45.3–46.8% protein, 18.0–19.6% fat, 3.0–4.2% ash and 4.3–4.5% crude fiber. Although, fermented samples had lower proximate values than the raw flour sample, fermentation increased protein and fat values but reduced carbohydrate, crude fiber and ash contents compared to the other flour samples. Ca and Mg were the dominant minerals in the flour samples. Apart from the raw soyflour sample, fermentation improved most of the mineral contents of the flours. Water and oil absorptions of raw seed flour were 124–155 g/kg and 69–71 g/kg, respectively. Cooking increased foam capacity and bulk density while autoclaving improved oil absorption and gelation of the flours. The chemical compositions and functional properties of the flours were influenced by processing and seed variety. Proper processing techniques may enhance the utilization of soybean.