Removal Of Pb?Cd From Rice Dregs Protein And The Characterization Of Product

Along with the improvement of people's living standards,the nutrition and edible security of food products were paid extensive attention.Rice dregs protein,a high-quality protein,can be used as raw material to produce rice protein products with high economic value.However,the existence of cadmium and lead in rice dregs protein were generally excessive,to solve this problem,the composite acid method was applied to take advantage of chelating effects of organic acid to remove Pb and Cd from rice dregs protein.Single-factor experiment combined with response surface analysis were applied to optimize the process.The structure and functional properties of rice dregs protein were determined simultaneously to maintain the flavor and nutritional value of rice protein as far as possible while the security was ensured at the same time.Specific contents of this research are as follows:1?Organic acids were used as chelating agent.The influence of acid species,addition amount,pH,treatment time and temperature of removal efficiency on Cd in rice dregs protein were explored,the optimal process were found to be: the additions of citric acid was 2.2%,pH was 3.0 and the temperature was 50 ?.Under this condition,the removal rate of Cd was 95.10% and the final content of Cd in rice dregs protein was 0.052 mg / kg.2?The optimal process to remove Pb from rice dregs protein were found to be:the pH was 3.5,the temperature was 50 ? and treatment time was 4.2h.Under this condition,the removal rate of Pb was 64.16% and the final content of Pb in rice dregs protein was 0.138 mg / kg,while the content of Cd reduced to 0.122 mg / kg.3?Primary,secondary and tertiary structure of treated and untreated rice dregs protein were measured.The composition of amino acid had not changed substantially,and the result of SDS-PAGE showed that the subunits of rice dregs protein were unchanged,and the nutritional value of rice protein had not been damaged.Secondary structure also had not changed.Results of fluorescence spectrometry showed that surface hydrophobicity of rice protein increased,emission peak wavelength movedfrom 365 nm to 358 nm,which indicate that the hydrophobicity of protein in micro-environment was enhanced.4?To enhance the practicability of these methods and provide foundation for future use in industrial production,eating quality and functional properties of rice dregs protein were determined.The color and granule of rice dregs protein was much more equalization after the treatment of citric acid,and the content of fat reduced.As for flavor,taste of sour and salty increased while the sensation of bitterness was reduced.The solubility of rice protein slightly decreased after the treatment of citric acid while foaming and emulsifying properties were enhanced.