Effect of gluconic acid rinsing on cadmium decontamination from rice protein

Cadmium (Cd) accumulation in rice protein has long been considered a significant threat to human health. In the present study, a costless and effective method based on gluconic acid (GA) rinsing of rice protein was developed to reduce Cd contamination in rice protein. Moreover, the effect of GA on the structural and functional properties of rice protein was evaluated. With liquid-solid ratio of 30 mL/g and oscillation time of 120 min, 96.0% and 93.6% of Cd were eliminated from rice protein-H and rice protein-L, respectively. In addition, the results of scanning electron microscopy, Fourier transform infrared, and sodium dodecyl sulfate polyacrylamide gel electrophoresis analyses showed that GA treatment did not significantly change the structural properties of rice protein. However, GA treatment increased foaming properties, water holding capacity, and oil holding capacity of the rice protein, without affecting its further applicability. Thus, the proposed GA rinsing method can be considered a green and efficient strategy to solve the issue brought by Cd residual contamination in rice protein. PRACTICAL APPLICATION: Given the advantages of green and efficient agriculture, gluconic acid (GA) has emerged as a powerful strategy for removing the Cd from rice protein. The method developed herein showed great potentials for applications in the manufacture of rice-based products.