Chemometric Approach for Discriminating the Effect of Raisin Syrup Sourdough on White Bread Aroma During Shelf Life

Raisin syrup sourdough is a popular traditional leavening method in Japan, yet its specific impact on bread aroma evolution and shelf-life stability remains scientifically underex-plored. This study characterized the fermentation dynamics and volatile profiles of raisin syrup sourdough bread compared to a commercial yeast control over a 3-day shelf life, utilizing comprehensive two-dimensional gas chromatography–mass spectrometry (GC×GC-TOFMS) and primary metabolite profiling of sugars, amino acids, and organic acids. The analysis resolved over 760 volatiles and revealed a fundamental kinetic divergence: while the yeast control exhibited a 24-hour metabolic lag, the raisin sourdough achieved rapid activation, establishing a higher initial volatile load immediately post-baking. Driven by Lactic Acid Bacteria dominance and extensive proteolysis, the sourdough’s acidic environment facilitated the retention of fruity esters and malty branched-chain aldehydes while effectively suppressing lipid oxidation markers like 9,17-Octadecadienal. Key aromatic markers, including Benzenepropanol and Octanoate , were significantly elevated and stabilized in the sourdough group. These findings demonstrate that raisin syrup fermentation generates a superior, stable aromatic profile, providing a scientific basis for optimizing clean-label artisan bread production in the Japanese market.