A new study provides the first detailed look at how industrial breakfast cereal manufacturing influences the formation of furans, alkylfurans, and acrylamide, which are process contaminants formed during thermal food processing and are associated with potential negative health effects. The findings highlight significant differences in contaminant formation across key steps such as extrusion cooking, puffing, toasting, and final coating.

For the study, four cereal companies provided cereal samples from different points in their production process, as well as gun-puffed grain products, for contaminant analysis. In model experiment on coatings, different coated samples were produced at the site of a project partner, which were then analyzed for contaminants. The study was conducted by researchers at the University of Münster and published in Food Control.

The researchers found that gun‑puffed cereals produced the highest concentrations of furans and acrylamide. Levels reached up to 140 micrograms per kilogram (µg/kg) of furan, 82 µg/kg of 2‑methylfuran (2-MF), 62 µg/kg of 2‑pentylfuran (2-PF), and 302 µg/kg of acrylamide. Higher puffing temperatures and pressures, which increase product expansion and reduce bulk weight, were associated with greater contaminant formation. Results also suggested that the type of cereal grain itself plays a major role in contaminant formation, although specific precursors remain unidentified.

Toasting generated high contaminant levels due to extreme heat and rapid moisture reduction. Immediately after toasting, average contaminant levels were 52 µg/kg furan, 24 μg/kg 2-MF, 27 μg/kg 2-PF, and 89 µg/kg acrylamide.

The study also uncovered clear differences between furan and acrylamide pathways during the production of extruded products. Most furan formation occurred during extrusion cooking, while acrylamide levels rose primarily during subsequent toasting and drying. Mean furan levels increased only slightly after toasting compared to levels seen after extrusion, but acrylamide levels nearly doubled.

Interestingly, when extrusion cooking resulted in high furan formation, little additional furan was generated during toasting, suggesting a possible limit due to volatility or degradation reactions.

The research also counters the assumption that sugar‑based coatings are a contamination source. Instead, coatings were shown to dilute contaminant concentrations in finished products due to added weight. Both industrial samples and controlled coating experiments confirmed that coatings typically contribute negligible amounts of furans or acrylamide.

Overall, the findings emphasized the need for cereal manufacturers to optimize processing steps for each process contaminant to account for formation differences, while also considering product quality. For example, although higher moisture during extrusion can reduce acrylamide, it does not lower furan formation. Reducing toasting temperatures could help mitigate furans, but may also affect product flavor and consumer acceptance.