Evaluation of the structure and function of whey protein concentrate combined with folic acid and l ‐ascorbyl 6‐palmitate

Abstract

Abstract BACKGROUND Whey protein concentrate 80 (WPC80) represents a highly promising carrier for bioactive compounds; however, the structural and functional consequences resulting from its noncovalent interactions with folic acid (FA) and l ‐ascorbic acid 6‐palmitate (LAP) remain incompletely understood. Hence, it is of practical importance to elucidate the effects of FA and LAP on the structural, functional, and physicochemical properties of WPC80, and to assess potential applications. RESULTS By constructing ternary complexes of WPC80–FA/LAP, the study characterized protein conformational changes using techniques including three‐dimensional fluorescence spectroscopy, surface hydrophobicity, protein flexibility, free sulfhydryl content, and SDS‐PAGE. In addition, foaming and emulsifying properties were measured, while processing stability and digestive release behavior were evaluated through spray drying and in vitro simulated gastrointestinal digestion. The results demonstrate that FA/LAP renders the structure of WPC80 more compact, reduces particle size, and promotes the conversion of tryptophan to N ‐formylkynurenine. Moreover, surface hydrophobicity was reduced by up to 63.07%, free sulfhydryl groups decreased by 14.07 μmol g −1 protein, and protein flexibility increased by 30.88%. Furthermore, FA and LAP significantly improved the interfacial properties of WPC80, enhancing its foaming capacity, emulsifying activity, and stability. In vitro digestion studies revealed FA release rates of 22.83–28.74% in the gastric phase and 62.86–84.69% in the intestinal phase, with strong antioxidant activity maintained post‐digestion. CONCLUSION This research elucidates the molecular and functional mechanisms of ligand–protein interactions, providing crucial theoretical and technical insights for developing protein‐based FA‐fortified food systems. © 2026 Society of Chemical Industry.