Formation of Maillard reaction products in a model bread system of different gluten-free flours

In this study, we determined the levels of Maillard-type products (furosine, free fluorescent advanced glycation end products, 3-deoxyglucosone, methylglyoxal, and N-ε-carboxymethyllysine) in a model gluten-free bread made of wholegrain white, brown, wild, red, and black rice flour, as well as of yellow and purple corn flour. The total protein, lysine, arginine, and cysteine contents were found to relate directly to the formation of Maillard-type products. The malvidin, ferulic, syringic, sinapic, and p-coumaric acids present in gluten-free breads were effective against the formation of furosine, fluorescent compounds, and dicarbonyls, but were ineffective in mitigating CML. Although the bread formulated with purple corn flour had the lowest levels of furosine and fluorescent compounds, this formulation led to an increase in N-ε-carboxymethyllysine and adversely affected the bread's aroma, on account of the presence of polyphenols responsible for a bitter aroma, which were at their highest concentration (1942.34 µg/g) in this bread.