General Components and Solibility of Current Commercial Soybean Flour

Thirteen samples of commercial soybean flour and isolated soybean protein were analyzed to determine the range of moisture, protein, fat, ash and carbohydrate content. In general components there was large differences between 13 samples, the protein and fat content of the samples varied 32.5-68.8% and 0.1-15.7%, respectively.The effect of pH value between 6.0 and 9.0 on the solubility of soybean flours was examined by the similar method to non-fat-dry milk. Exposure of soybean flours to sodium hydroxide solution at high pH levels (pH 8.8) markedly increased its solubility. This solubility of soybean flours was in good agreement with Nitrogen Solibility Index (NSI).Furthermore, yoghurt-like-products prepared from soybean flour were determined for the hardness and texture. The low level soybean flours of solibility and NSI that were added in yoghurt-like-product formed yellow precipitate, granular texture and increased soybean flavor.Solubility and NSI measurement would be a useful key for selection of soybean flour suitable for yoghurt-like-product.