Evaluation of the Level of Aflatoxins in Raw Peanuts and Reduction Levels of Aflatoxins in Peanuts through Nixtamalization (Lime Treatment) and Calcium Enrichment

Abstract

Nixtamalization has been widely used as a method of reducing aflatoxin contamination in peanuts as well as in calcium enrichment. The aim of this study is to investigate the effects of nixtamalization on aflatoxin and nutrient content in peanuts among wholesalers and retailers at Nyamakima Market in Nairobi, Kenya. A representative sample was drawn from a population of 70 market vendors using a systematic random sampling technique, resulting in 35 raw peanut samples for analysis via ELISA to determine initial aflatoxin levels. These samples were then subjected to nixtamalization treatments of 4, 8, and 16 minutes. The findings revealed that the average concentration of total aflatoxins in peanuts initially exceeded the accepted safety limit, with 71% of the samples failing to meet the standards. However, nixtamalization led to a substantial reduction in aflatoxin levels by 49%, 48%, and 50% after treatment durations of 4, 8, and 16 minutes, respectively. Statistical analysis, including ANOVA and Two-sample T-tests, confirmed significant distinctions between initial and final mean aflatoxin levels post-treatment, as well as variations between treatments. The study also observed a significant variation in calcium levels between the different time treatments, supported by linear regression analysis, which demonstrated a robust correlation between time treatments and calcium levels (R2=0.83, P=0.011). Furthermore, the analysis revealed significant differences in mean moisture contents across various treatments (P=0.000), and a linear relationship between mean moisture content and exposure time (P=0.02). The results emphasize the positive impact of nixtamalization in reducing aflatoxin levels and enhancing calcium content in peanuts. However, it is crucial to note the negative effect on moisture content, which exceeded stipulated limits, potentially raising concerns about product safety and quality.