Stability of fumonisin B1 and its bioaccessibility in extruded corn-based products

Fumonisins are a group of mycotoxins commonly associated with corn-based products and require innovative alternatives to control exposure to its toxicity. The objective of this research was to determine the effect of amylose and resistant starch on fumonisin B1 (FB₁) levels in extruded corn-based products as well as the toxin bioaccessibility upon digestion. Cornmeal contaminated with FB₁ (1.5 µg/g) was extruded alone or combined with high-amylose corn starch (20%, w/w). FB₁ was quantified both in the unextruded and extruded products by HPLC (high-performance liquid chromatography) fluorescence detector with pre-column derivatization. Samples were then subjected to an in vitro digestion model to evaluate the stability of the interaction between FB₁ and the corn matrix extruded. The addition of high-amylose corn starch further reduced the detection of FB₁ (74.9%), when compared with the effect of the extrusion alone (66.0%), confirming the binding of FB₁ with the macromolecules or resistant starch. The bound fumonisin was stable upon simulated gastric digestion, and the duodenal bioaccessibility of free FB₁ was lower than 35% when high-amylose corn starch ingredient was used in the product. Principal component analysis (PCA) showed that high-amylose corn starch and resistant starch content influenced the reduction of FB₁ and its duodenal bioaccessibility. This study for the first time shows that addition of high-amylose corn starch during extrusion is an innovative strategy to reduce FB₁ release under digestive conditions, therefore useful in mitigating the exposure to this mycotoxin.