Unveiling the dynamic response of volatile development during barley malt roasting via untargeted and pseudo-targeted flavoromics: A time course study

Roasting is an efficient way to enhance the aroma of malts. However, the dynamic response of volatile development throughout roasting has been rarely explored. In this study, multiple omics approaches were applied to systematically investigate underlying mechanisms of volatile development at a time-course manner during roasting. Roasted malts (RMs) with color ranging from 2° to 243°L were sampled at six roasting stages (RT0-5), and their free amino acids and reducing sugars were profiled and quantitated. Additionally, fatty acids (FAs) of these RMs were depicted via untargeted and targeted lipidomics, unveiling nine differentiated FAs across the six RTs. Furthermore, a comprehensive flavoromics integrating untargeted, pseudo-targeted, and targeted analyses was employed to characterize volatile development across RTs with 14 annotated compounds. Notably, non-linear patterns have been observed in malt coloration, precursors consumption, and volatile development for the first time. This work provided practical guidelines for the production and application of RMs.