Cooking elements affecting on heavy metal concentration in rice

In recent years, heavy metal contamination of rice in different parts of the world has raised concerns about its safety and provoked crisis in it's global production and trade. In Iran, also some studies have reported on the heavy metal contamination of native products. However, the concentration of heavy metals in rice grain could be influenced through preparation and cooking. this study aimed to review the related literature in order to categorize the most important studied elements in cooking which has impact on its the heavy metal concentration. The scientific databases were searched and 51 relative articles were obtained from 1994 to 2012 from which 18 scientific papers were chosen and reviewed. Result of review literature revealed that cooking method, heavy metal concentration in cooking water, temperature of cooking water, type of heavy metal, type of cooking utensil, rice variety and the volume ratio of rice to water were regarded as the influential factors which were discussed for their individual or combined effects. Cooking method seems to have the greatest impact, however its effect seems to be dependent on the type of contaminant element. Using the cooking methods which cooking water is not removed during the cooking, Heavy metal concentration of cooking water effectively increases the concentration of the cooked rice. with the exception of a few evidence on the aluminum transmission in to the cooked rice, difference in cooking utensil, do not have impressive effect. Rice variety, the volume of raw rice as well as the primary concentration of heavy metals in raw rice, all have minor effects on the heavy metal content of cooked rice.