Nutritional composition and heavy metal profile of Nigerian rice varieties

This study was carried to assess the nutritional composition and heavy metal profile of Nigerian rice varieties. A total of one hundred samples consisting of twenty five samples each of four varieties of white unpolished Nigerian local rice Oryza glaberrima (Ofada rice, Abakaliki rice, Ekpoma rice and Igbimo rice) were purchased from Ofada in Ogun State, Nigeria. Flour samples produced from the rice varieties were evaluated for nutritional (proximate, amino acids and vitamins profile analyses) qualities and heavy metal profile. Results showed (P≤0.05) that the protein contents in % ranged from 6.72±0.05 – 6.93±0.06% while the concentration (μg/g) of Ar, Pb and Cd ranged from 1.30±0.05 to 1.45±0.05, 0.89±0.02 to 0.98±0.04 and 1.12±0.01 to 1.30±0.03, respectively. The protein contents were relatively high, although, all the four Nigerian rice varieties were deficient in lysine; arginine and methionine while the non-essential amino acids glycine and glutamic acid, although lysine and methionine were detected in very low quantities. The quantity of heavy metals obtained in the four Nigerian rice varieties flour samples were generally below the maximum acceptable limits and therefore constitute health risk to the consumers.