ABSTRACT
Corn sauce, an ingredient obtained from the fermentation of enzymatically hydrolyzed corn starch and used in culinary applications to provide savory taste, was investigated in this study. The links between its sensory properties and taste compounds were assessed using a combination of analytical and sensory approaches. The analyses revealed that glutamic acid, sodium chloride, and acetic acid were the most abundant compounds, but they could not explain entirely the savory taste. The addition of other compounds, found at subthreshold concentrations (alanine, glutamyl peptides, and one Amadori compound), contributed partly to close the sensory gap between the re-engineered sample and the original product. Further chemical breakdown, by a sensory-guided fractionation approach, led to the isolation of two fractions with taste-modulating effects. Analyses by mass spectrometry and nuclear magnetic resonance showed that the fractions contained glutamyl peptides, pyroglutamic acid, glutamic acid, valine, N-formyl-glutamic acid, and N-acetyl-glutamine.
Subject(s)
Flavoring Agents/chemistry , Flavoring Agents/isolation & purification , Zea mays/chemistry , Amino Acids/analysis , Amino Acids/metabolism , Chemical Fractionation , Chromatography, High Pressure Liquid , Corynebacterium glutamicum/metabolism , Fermentation , Glutamic Acid/analysis , Glutamic Acid/metabolism , Humans , Mass Spectrometry , Taste , Zea mays/metabolism , Zea mays/microbiologyABSTRACT
[reaction: see text] A novel strategy to generate thioester peptides compatible with Fmoc chemistry is presented. Peptide-C(alpha)oxy-(2-mercapto-1-carboxyamide)ethyl ester undergoes an O to S acyl shift during ligation and the newly formed thioester intermediate reacts with an N-terminal cysteine fragment generating a product with native amide bond at the ligation site.
