Comparative study of nutrient composition of commercial brown, parboiled and milled rice from Brazil

The present work aims to compare the chemical composition of commercial samples of brown, parboiled brown, parboiled milled and milled rice, and the contribution of each mineral to the Recommended Dietary Allowance (RDA). The chemical composition was determined according to official methods and an inductively coupled plasma-based technique was used to analyse the minerals. The results showed protein (N×5.7) and crude fat contents in all rice forms similar to literature data with some differences in ash contents, mainly between milled samples. Parboiled milled rice showed 18% ash enrichment in comparison with milled rice, and higher contents of K and P. Lower contents of Mn, Ca and Zn were observed, even though contents of other nutritionally important elements were basically similar to milled rice. The brown rice analysed showed concentrations of P, Mn and Na lower than those reported in literature, indicating the usefulness of selecting nutritionally promising varieties for commercial production. Se, Mn, Cu and Zn, reaching 35% of the RDA, depending on the element and the form of rice, presented the highest nutritional contribution. Macroelements, which are the most affected by parboiling and milling, showed a low contribution to the RDA in all forms of rice.