Trace Metals, Crude Protein, and TGA-FTIR Analysis of Evolved Gas Products in the Thermal Decomposition of Roasted Mopane Worms, Sweet Corn, and Peanuts

Overview

This study measured trace metals (tAs, Cd, Co, Cr, Ni, Pb) alongside crude protein in three roasted food products commercially available in South Africa: mopane worms (Gonimbrasia belina), sweet corn, and peanuts. The key finding was that total arsenic concentrations in all three products exceeded maximum allowable threshold limits, while cadmium in peanuts also exceeded acceptable limits, raising food safety concerns. ICP-OES analysis was performed following microwave-assisted acid digestion.

Key numbers

Arsenic (tAs): exceeded threshold limits in all three matrices (specific values not extracted from abstract, flagged for full-table review). Cadmium (Cd): above acceptable limits in peanuts. Cobalt (Co), chromium (Cr), nickel (Ni), and lead (Pb) were also measured. Analytical method: ICP-OES; sample prep: microwave-assisted HNO3/H2O2 digestion. Crude protein was analyzed by the Kjeldahl method. TGA-FTIR thermal decomposition analysis was also performed.

Methods (brief)

ICP-OES following microwave-assisted acid digestion. Three food commodities: roasted mopane worms, sweet corn, and peanuts, commercially sourced in South Africa. Comparison against South African and international threshold limits. Sample n=3 (one per commodity).

Implications

Certification: Edible insects are an emerging category of concern; tAs exceedance in mopane worms is relevant to HMT&C as insect-protein ingredients enter food products. Peanut Cd exceedance is relevant to peanut-containing product certification. Courses: Illustrates that emerging protein sources (insects, legumes) carry measurable heavy metal loads that may exceed regulatory thresholds. App: Supports contamination_profile entries for edible-insect and peanut ingredients.

Wiki pages updated on ingest

• Peanuts
• edible-insects
• Cadmium
• tAs

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