Growth and transcriptional response of Salmonella Typhimurium LT2 to glucose–lysine-based Maillard reaction products generated under low water activity conditions

Abstract

This study reports the growth and transcriptional responses of Salmonella Typhimurium LT2 to Maillard reaction products (MRPs) generated in a simulation of the reaction during food processing and storage. Maillard reactions between N-α-acetyl-lysine and glucose were stopped at 4, 23, or 143h to generate sub-samples with prevailing Amadori compound, advanced glycation end products (AGEs), or melanoidins, respectively. When used as the only carbon source, MRPs' disappearance occurred during S. Typhimurium secondary logarithmic growth phase after the glucose available in the MRP reaction mixtures was exhausted. Of the three MRP sub-samples, the Amadori compound was the preferred carbon source (98% disappearance). Decreases in AGEs (37%) and melanoidins (15%) also occurred. Transcription profiles of cells grown on the MRPs revealed predominant up-regulation of genes associated with the functional groups of energy metabolism, fatty and phospholipid metabolism, cellular process, and regulatory functions, and general down-regulation of the genes in the groups of amino acid biosynthesis, protein synthesis and transcription, transport and binding proteins, and DNA metabolism.