Abstract: 【Objective】To establish a highly efficient extraction technology for rice bran protein under low alkalinity and temperature, and determine its physicochemical properties.【Method】Use quadratic general rotary unitized design to determine the optimal extraction process. The solubility, emulsibility and frothing capacity of rice bran protein at different pH, temperatures and ion concentrations were investigated. Kjeldahl’s method was used to measure the solubility, centrifugation method to measure the emulsibility, and volume method to measure the frothing capacity.【Result】The optimum extraction conditions were: pH 11, temperature 40℃，time 120min, and the yield could reach up to 81.1% under such conditions. The solubility of rice bran protein was the lowest around isoelectric point, and the solubility was increased with the increase of temperature, while it was reduced due to ion presence. Effects of pH, temperature and ion concentration on emulsibility were similar to those effects on solubility. The higher the concentration pf rice bran protein the better of its emulsibility. Its frothing capacity was the lowest while foam stability was the highest around isoelectric point. Its frothing capacity was increased by suitable heating, and it was also significantly improved with the increase of ion concentration and protein concentration.【Conclusion】The yield of rice bran protein can reach up to 81.1% on low pH and temperature. The properties of rice bran protein obtained in this way are good, indicating good potential for applications.

Key words: Rice bran protein, Extraction technology, Properties, Solubility, Emulsibility, Frothing capacity