Endogenous Peptides Identified in Soy Sauce Aroma Style Baijiu Which Interacts with the Main Flavor Compounds during the Distillation Process

Endogenous peptides in Chinese baijiu have been recently reported. However, little information is available on their correlation with the main flavor substances. One hundred and forty-six peptides, consisting of more bitter amino acids and key amino acids responsible for bioactivity, were identified in tail liquor using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Additionally, the content of endogenous peptides increased gradually with distillation time, showing a high negative correlation with total esters (r = −0.929) and total alcohol (r = −0.964) but presented a moderate positive correlation with the total acid content (r = 0.714). The results of the correlation analysis between them were further proved by molecular docking, which showed that these endogenous peptides in baijiu interacted with the main flavor substances via hydrogen bonds. This study clarifies the dynamic changes of endogenous peptides during distillation and provides a theoretical reference for the relationship between these peptides and the main flavor substances.