Differential Non-Volatile Metabolomics in High- and Low-Alcohol Strong-Flavor Baijiu by Non-Targeted Approach

Alcohol level is a critical quality parameter in Chinese baijiu, significantly influencing its flavor profile, sensory characteristics, and overall quality, which in turn affect consumer preferences and the development of the liquor industry. Understanding the non-volatile compounds in strong-flavor baijiu (SFB) is essential for elucidating its taste and mouthfeel characteristics. This study aims to identify non-volatile compounds using a non-targeted metabolomics approach and investigate the differences between high- and low-alcohol SFB from the Jiangsu region. A total of 647 non-volatile compounds were quantified. The key differential metabolites were screened among different samples. In total, 110 key differential non-volatile compounds were identified and quantified, which displayed significant differences between high- and low-alcohol SFB samples and showed notable similarities in compound types. Furthermore, the variation in non-volatile profiles among samples of the same brand but different alcohol levels was investigated. The different brands and origins of SFB samples were identified using OPLS-DA. The results indicated that the key non-volatile metabolites in most of the high-alcohol samples were higher than those in low-alcohol samples. This study provides valuable insights into the impact of alcohol level on the non-volatile composition of SFB, offering a theoretical foundation for flavor characterization, quality control, and standardization in baijiu production.