Occurrence of metal ions in rice produced in Uruguay

Abstract

The United Nations General Assembly declared the year 2004 the International Year of Rice under the concept "Rice is Life". The largest nutritional problems occurring globally are protein-energy malnutrition, Ca, Fe, I, Zn and vitamin A deficiencies. Being rice the staple food more consumed worldwide, outstanding care is taken on its composition levels.
Uruguay has emerged as medium-size rice producer and Latin America's major rice exporter, and is now amongst the world's top ten. Thus, the knowledge of toxic as well as micronutrient elements is very important. Here is reported the determination in forty nine samples of rice (Oryza sativa L.) of As, Cd, Cr, and Pb by ET AAS in samples digested by dry ashing, and Ca, Co, Cu, Fe, K, Mg, Mo, Mn, Na, Ni and Zn by FAAS and Hg by CV AAS using microwave-assisted decomposition.
The amount of all the metal ions studied in this work fall within the range typical of rice around the world. All the rice samples tested showed lower levels of As, Cd, Hg and Pb than the maximum limit permitted by governmental and international organizations.
Potassium was the most abundant mineral followed by Mg and Ca and amongst microelements the presence of Cu, Fe, Mo, Mn, Na and Zn was outstanding.
The milling process highly affects the contents of K, Mg, Mn, Na and Zn while little influence has on Ca, Co, Cu and Fe concentrations.
Unexpected loss of Ca, Fe and Mn during parboiling process was detected.