Heavy metals screening of rice bran oils and its relation to composition

Authors: Bakota, Erica; Dunn, Robert; Liu, Sean

Submitted to: European Journal of Lipid Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2015
Publication Date: 3/19/2015
Citation: Bakota, E.L., Dunn, R.O., Liu, S.X. 2015. Heavy metals screening of rice bran oils and its relation to composition. European Journal of Lipid Science and Technology. 117(9):1452-1562. doi: 10.1002/ejlt.201400443.

Interpretive Summary: Rice bran oil has been gaining popularity as a cooking oil in recent years. However, there has also been a growing concern among consumers regarding arsenic concentrations in rice and rice products. It is true that rice plants take up arsenic at a higher rate than most other grain crops, and as a result, arsenic and other metals may accumulate in the rice grain. No limits have been set in the United States or Europe for arsenic concentrations in foods, and furthermore, arsenic levels in rice bran oil have not been investigated at all, to our knowledge. In this work we characterize both crude and refined rice bran oils, including levels of arsenic and other heavy metal contaminants, including lead, mercury, cadmium, and zinc. We found that some rice bran oils contain heavy metal contaminants, although it is unclear at this point whether the levels of these contaminants are sufficient to pose a risk to the general population.

Technical Abstract: Rice bran oil contains beneficial compounds that contribute to the high stability of the oil itself, as well as the health of consumers. As a result, rice bran oil has been growing in popularity and is now widely used in many countries. However, concerns have surfaced in recent years related to the heavy metal, and specifically arsenic, content of rice and products derived from rice. Rice is known to take up arsenic at a higher rate than other grain crops. As arsenic is known to have adverse health effects in humans, acceptable levels have been set in the United States for arsenic concentrations in drinking water. No limits have been set in the United States or Europe for arsenic concentrations in edible products, and furthermore, arsenic levels in rice bran oil have not been investigated. In this work we characterize both crude and refined rice bran oils, including levels of arsenic and other heavy metal contaminants, including lead, mercury, cadmium, and zinc. We also verified metal concentrations through an independent, external analytical laboratory. It was found that some rice bran oils contain heavy metal concentrations well above those recommended for drinking water. In general, though not in every case, crude rice bran oil contained higher metal concentrations than refined rice bran oils.