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Removal of cadmium from rice proteins by soaking with hydrochloric acid or ethylene diamine tetraacetic disodium solutions
- Feng, Wei, Wang, Tao, Dong, Tiantian, Xu, Pengcheng, Zhang, Tianqi, Luo, Xiaohu, Wang, Li, Wang, Ren, Chen, Zhengxing
- Journal of cereal science 2019 v.85 pp. 35-40
- EDTA (chelating agent), acid treatment, amino acid composition, cadmium, emulsifying, ethylene, foaming, hydrochloric acid, mineral content, pH, soaking, temperature, washing
- In this study, removal of cadmium (Cd2+) from rice proteins (RPs) by soaking with hydrochloric acid (HCl) or ethylene diamine tetraacetic disodium (EDTA-2Na) solutions was reported. For HCl-soaking, Cd2+ removal reached equilibrium within 30-min treatment, and the size of RPs particles and reaction temperature had negligible effects on the Cd2+ removal rate (RCd). However, extra washing of HCl-treated RPs by distilled water or acid solution can further enhance RCd effectively. The reaction pH had a profound effect on RCd, and the reduction of pH values from 5.5 to 4 can boost RCd from 16.4% to 92.3%. On the other hand, by increasing the concentration of EDTA-2Na from 10 μg/mL to 40 μg/mL at pH 7, RCd increased from 69.1% to 92.0%. However, the reduction of pH resulted in the formation of insoluble conjugates consisting of RPs, EDTA and Cd2+, therefore lowering RCd. Both of the two methods reduced the mineral content in RPs, but had no significant impact on their amino acid compositions. Furthermore, compared to the soaking by EDTA-2Na, acid treatment weakened the emulsifying and foaming capabilities of RPs to a greater extent.