Reducing the cadmium, inorganic arsenic and dimethylarsinic acid content of rice through food-safe chemical cooking pre-treatment

Cadmium, inorganic arsenic and, potentially, dimethyl arsenic acid are carcinogens widely elevated in rice. Here it was identified that the food-safe and common cadmium chelator citric acid efficiently removed cadmium from intact grain via pre-soaking procedure, while also reducing arsenic species. A twostep pre-soaking stage was developed whereby rice was first incubated, at ambient temperature, in 1 M citric acid for 12 h, and then in 1 M calcium carbonate for another 12 h, the latter step to neutralize pH, followed by cooking. When 10 different individual types of rice were processed in such a way this resulted in removal rates of 79% for cadmium, 81% for inorganic arsenic and a 66% for DMA. The technology is particularly suitable for bulk food processing and could be deployed in the most cadmium and arsenic impacted regions where rice is a staple.

Automated summary

Cadmium, inorganic arsenic, and potentially dimethyl arsenic acid, which are carcinogens commonly found in rice, can be efficiently removed using citric acid as a chelator. A two-step pre-soaking procedure using citric acid and calcium carbonate was developed to reduce these contaminants in rice, with removal rates of 79% for cadmium, 81% for inorganic arsenic, and 66% for DMA. This technology is suitable for bulk food processing and can be used in regions where rice is a staple and contaminated with cadmium and arsenic.