Decoding the bioactive peptides and metabolic fingerprints of whey derived from dairy fan processing by-products

Whey contains abundant nutrients and bioactive compounds with health benefits, but functional peptides and metabolites in Dairy fan whey (Whey generated during dairy fan processing, DFW) remain underexplored. Therefore, this study identifies DFW nutritional profile and bioactivity via peptidomics, nontargeted metabolomics, and in vitro experiments. The results showed that a variety of bioactive peptides were identified, including antioxidant peptides and angiotensin-converting enzyme (ACE) inhibitory peptides. Four antioxidant peptides interact with Keap1 via hydrogen bonds and salt bridges, thereby exerting antioxidant effects and regulating the Keap1-Nrf2/ARE pathway. In vitro assays confirmed that DFW scavenged DPPH, ABTS, and hydroxyl radicals, demonstrating strong antioxidant activity. Additionally, 919 metabolites were identified in DFW and conventional whey (W), including 15 characteristic compounds such as 4-aminobutyric acid, histamine, and pyridoxine. These characteristic metabolites exhibit antioxidant, anti-inflammatory, and immunoregulatory activities. Compared with W, DFW contains more characteristic nutrients. Overall, this study provides a theoretical basis for the high-value utilization of DFW.