Effect of Nixtamalization on Aflatoxins, Functional and Acceptability of Maize from Mulindi, Rwanda

Abstract

Rwanda relies highly on maize for human food as well as for animal feed and industrial uses. However, high temperature and wet climate conditions in Rwanda favor the growth of fungi that may lead to mycotoxin contamination in maize and subsequent degradation of its quality. Therefore, this study aimed to assess the effect of nixtamalization on the aflatoxins, the functional and acceptability of maize grains from Mulindi, Rwanda. The maize samples were collected from the Mulindi market in Rwanda; representative samples were collected by the guidelines for sampling food for mycotoxin determination. Subsequently, the treated maize samples were dry-milled to produce fine flour, and the flour obtained was analyzed for swelling capacity, water absorption capacity, water solubility, acceptability, and aflatoxins, which were quantified by the HPLC method. The HPLC results showed that the highest total aflatoxin level in maize grains was 44.99 ppb. Cooking maize in water and calcium hydroxide of 1% resulted in a reduction of aflatoxin with degradation percentages of 25% and 88%, respectively. However, in all treatments, aflatoxins B1 and B2 were less reduced compared to aflatoxins G1 and G2. Cooking maize in pure water showed the lowest reduction of aflatoxin compared to the other treatments. However, cooking maize in water with 1% calcium hydroxide decreased aflatoxin to a higher percentage. Cooking maize in lime enhanced the swelling capacity, water absorption capacity, and water solubility of maize, as well as its acceptability. However, the nixtamalization process was observed to reduce aflatoxins levels in maize and improve the functional properties of maize, and therefore, its application could be encouraged for safe products in the market.