Effects of Processing Methods on the Heavy Metal Contents of Yam (Dioscorea spp.) Produced in Benue State

Abstract

In this paper, effects of processing methods on heavy metal contents of yams (Dioscorea spp.)
produced in Benue State was investigated. The study analysed chemical content of samples of yam
tubers to determine the effectiveness of cooking methods on heavy metal reduction. Results showed
that while, cooking methods can reduce heavy metal content, the levels of the mean concentration
of Arsenic, chromium and lead often exceeded international safety standards. Findings also revealed
that among the methods, frying demonstrated the most significant reduction, followed by boiling
and roasting. Peeling yams before boiling and rinsing, further enhanced heavy metal reduction.
Boiling was particularly effective due to mechanisms of solubility enhancement, diffusion, leaching
and water discard. Fertilizer residues, which can carry heavy metals, contributed to the elevated
levels in yams. Based on these results, the study recommends that regulation on agrochemical use
should be enforced along with farmer education on proper application and disposal. Implementing
best practices throughout the yam cultivation, storage, transportation, and preparation processes
can help mitigate heavy metal contamination and associated health risks.