Characterization of binding behaviors of Cd2+ to rice proteins

• Published in: Food chemistry Vol. 275; pp. 186 - 192
• Main Authors: Feng, Wei, Dong, Tiantian, Li, Keqiang, Wang, Tao, Chen, Zhengxing, Wang, Ren
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2019
• Subjects: Binding characteristics; Cadmium; Coordination competition; Rice protein; Cadmium; Rice protein; Binding characteristics; Coordination competition
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2018.09.123

•The binding behaviors of cadmium to rice proteins were innovatively studied.•The binding of cadmium to rice proteins was thermodynamic favored.•The cadmium in rice proteins can be removed by acids or food metals ions. In this paper, for the first time the binding behavior of cadmium (Cd2+) to rice proteins (RPs) was studied. The results showed that the equilibrium of binding was reached within 30 min at 303 K with a maximum binding amount (q) of 15.26 mg/g, and the pH was an important factor positively influencing q. At both 308 K and 313 K, the binding of Cd2+ to RPs belonged to spontaneous, endothermic interactions with high-affinity, assigned to a multidentate coordination. Except for acetate, all the investigated competing coordination agents, such as edetate, pyrophosphate and citrate, showed inhibitory effects on RPs-Cd2+ binding, and edetate seemed to be the most effective one. At pH 6.5, calcium, copper and zinc began to restrict RPs-Cd2+ binding when the metal ion concentration reached 500 mg/kg, and the decreasing of pH would strengthen the inhibitory effects of the investigated metal ions including ferric ions.