Integrative LC-MS and GC-MS metabolic profiling unveils dynamic changes during barley malting

Authors: RANI, HEENA - Oak Ridge Institute For Science And Education (ORISE); Whitcomb, Sarah

Submitted to: Journal of Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2024
Publication Date: 10/18/2024
Citation: Rani, H., Whitcomb, S.J. 2024. Integrative LC-MS and GC-MS metabolic profiling unveils dynamic changes during barley malting. Journal of Food Chemistry. 463(4). Article 141480. https://doi.org/10.1016/j.foodchem.2025.141480.
DOI: https://doi.org/10.1016/j.foodchem.2024.141480

Interpretive Summary: During malting a quiescent barley seed transforms into a shelf-stable package of enzymes, fermentable sugars, and flavorful compounds for the brewing, distilling, and baking industries. And although malting is an ancient process, relatively little is known about the myriad changes to metabolism that occur during this process which ultimately affect the quality and safety of malt. Our study used advanced analytical techniques to measure approximately 5,000 metabolites and to analyze the metabolic changes that occur during the malting process. The most pronounced metabolic shifts occurred during early germination and kilning, highlighting their crucial role in determining malt quality and enhancing flavor. We also observed an increase in various anti-microbial metabolites during these stages, emphasizing the importance of the microbial ecosystem in shaping the final malt quality.

Technical Abstract: Malting, a crucial process for beer production, involves complex biochemical transformations affecting sensory attributes and product quality. Despite extensive research on storage carbohydrates and proteins involved in malting, a detailed understanding of metabolic alterations during this process remains elusive, limiting our ability to assess and enhance malt quality. Our study employed untargeted GC-MS and LC-MS metabolite profiling to elucidate these changes across six malting stages: dry seed, post-steeping, germination (DOG1, DOG3, DOG5), and kilning. After data processing, we identified a total of 4980 known metabolites, with approximately 82% exhibiting significant changes. Statistical analysis revealed stage-dependent metabolic shifts, with most significant shifts occurring from DOG1 to DOG3 and during kilning. Dynamic changes in chemical classes and metabolic pathways provided insights into processes critical for malt quality and beer production. Additionally, metabolites associated with antimicrobial properties and stress responses were identified, underscoring the interplay between barley and microbial metabolic processes during malting.