New insights into nonenzymatic browning of non-PDO Italian hard cheese through a metabolomics approach

Nonenzymatic browning poses a severe problem to the dairy industry, causing economic losses. In this work, an untargeted metabolomics approach based on ultra-high-performance liquid chromatography coupled with Orbitrap mass spectrometry was used to investigate the discoloration found on the inner parts of nonprotected designation of origin Italian hard cheese. Alkyl-pyrazines, imidazo-quinoxalines and β-carbolines were the best markers, suggesting the involvement of microbial methylglyoxal in modulating the browning defect. A better understanding of the microbial composition of natural whey starter could be of interest in future studies to better elucidate the biochemical mechanisms involved and to help generate discriminant metabolites.