Abstract

Cereals, which are commonly consumed in Africa and other regions because of their nutritional complementarity and potential to alleviate malnutrition, have been observed to be susceptible to mycotoxin contamination. The presence of aflatoxins in food and agricultural commodities is a significant economic issue due to their highly carcinogenic nature, capacity to directly impact DNA structure, potential to cause foetal abnormalities and miscarriages, and ability to weaken immune systems. This study was conducted to determine the proximate composition, amino acid content and aflatoxin levels of selected cereals retailed in Wukari, Taraba State. A total of 27 samples of various agricultural commodities, including maize, rice, and millet were procured from grain vendors operating in the markets of Wukari metropolis. These markets are namely Wukari New Market, Wukari Old Market and Dorowa Market which has distance of above 40km from Wukari city. The collection of samples took place during the period spanning from April to May of the year 2023. Experimental procedures for proximate composition were carried out using the standard methods of Association of Official Analytical Chemistry, amino acid analysis was carried out using acid hydrolysis on grain samples employing the amino acid analyser while aflatoxin levels in samples were determined using the Enzyme linked immunosorbent assay (ELISA) method. The results of proximate composition for cereals ranged from 2.56-4.80% ash content, 1.48-4.12%, crude fibre, 9.21-15.78% crude protein, 2.15-3.14% ether extract, 68.05-75.9% nitrogen free extract and 4.12-6.56% moisture. The results of amino acid analysis for cereals ranged from 0.11% histidine, 0.21-22.72% isoleucine, 0.49- 0.93% leucine, 0.12-0.27% lysine, 0.14-0.84% methionine, 0.31-2.62% phenylalanine, 0.16-14.22% threonine, 0.00-0.01% tryptophan, 0.29-8.21% valine and 0.36-0.80% arginine, 0.38%-6.46% aspartic acid, 0.27%-5.63% serine, 1.39-23.1% glutamic acid, 0.15%-8.34% proline, 0.21-0.90% glycine, 0.09%-8.46% cysteine, 0.09%-0.86% cysteine and 0.18%-2.82% tyrosine. There were no significant differences in the aflatoxin levels of millet samples purchased from all the markets. Aflatoxin levels in cereals retailed in Wukari, Taraba State ranged from 3.11-13.10µg/kg in maize samples, 6.13-15.4µg/kg in millet samples, and 0.47-1.0µg/kg in parboiled rice samples. These aflatoxin levels were within the permissible limits for total aflatoxins recommended by FDA and NAFDAC for all products intended for food, hence the cereals analysed in this study are safe for human consumption. 

Keywords

Cereals, Aflatoxin, Proximate Composition, Nutrition, Agriculture