Preparation and properties of okara protein

Okara protein was extracted from dry okara by alkali-solution and acid-precipitation.Extraction conditions of okara protein were optimized by orthogonal experiment,and the properties of okara protein were determined.The results showed that the optimal extraction conditions were as follows: ratio of solid to liquid 1∶ 30,pH 12.71,alkaline extraction temperature 50 ℃,alkaline extraction time 1 h.Under these conditions,extraction rate of okara protein was 75.05%.The foaming stability,emulsion stability and amino acid composition of okara protein were similar to SPI,while the solubility,foamability and emulsibility of okara protein were comparatively worse than that of SPI.