Revelation of germination days on the aroma variations of roasted barley malts via untargeted and targeted flavoromics with HS-SPME-GC-MS/olfactometry

Abstract: In this study, roasted barley malts (RM) were prepared from consecutive three different germination days (3, 4, 5D), and the aroma similarity and disparity among RM and its base malt (BM) were compared via an HS-SPME-GC-MS based flavoromics. Besides, the wort color and primary precursors, free amino acids, free reducing sugars, and fatty acid compositions were all determined. The results showed that despite the variations in each primary precursor in BM, roasting could basically flatten the variations induced by germination days. Moreover, with untargeted and targeted flavoromics, 77 aromas were identified, including 36 odor-active aromas. Based on the quantitation of 53 aromas, a PLS-DA model was applied to differentiate all samples by 17 aromas with VIP ≥ 1. As for aroma balance, RM4D outstood due to a pleasant nutty note with the highest sweet-to-nutty index of 0.8. This work answered how would germination process impact the aroma of RM.