Comparative Analysis of Metal Elements in Rice Bran from Selected Regions of Kenya

Abstract

Aims: Rice bran a by-product of rice milling holds significant nutritional and health value to humans and livestock. However it can accumulate both nutritionally important and toxic metal elements and therefore realization of the nutritional benefits while minimizing potential toxic effects is important. To shed light on this, profiling of metal elements was done. Study Design: A comparative research design was adopted for this study. Place and Duration of Study: Rice samples were collected and milled at Lungalunga, Mwea and Ahero in Kenya and analyzed at the Analytical Chemistry laboratory of the Kenya Plant Health Inspectorate Service (KEPHIS) between July 2023 and January 2024. Methodology: A total of 18 rice bran samples, six from each of these study regions were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP- OES). Results: Rice bran from Lungalunga had the highest amount of Potassium (15148.94mg/Kg), Manganese (290.26mg/Kg), Zinc (76.56mg/Kg), Copper (11.76mg/Kg), Arsenic (0.77mg/Kg) and, the only samples in which Cadmium (0.01mg/Kg) was detected. On the other hand, rice bran from Mwea had the highest amounts of Magnesium (6628.62mg/Kg) and Selenium (2.23mg/Kg) while that from Ahero had the highest amounts of Iron (269.64mg/Kg) and Chromium (2.41mg/Kg). Other than the levels of Magnesium and Zinc from Ahero which were significantly lower than that from the other two regions and; Chromium from Ahero which was significantly higher than that from Mwea, all the others did not vary significantly (p=0.05). Mercury and Lead were not detected in any sample. Conclusion: Kenyan rice bran contains high amounts of nutritionally important metal elements that can be used to enrich food and feeds. However, levels of Arsenic which is toxic were higher than the Codex limit for husked and polished rice and; for cereal foods.  This calls for quality control and surveillance measures that guarantee health benefits and food safety.