Pectin modification affects naringin bioaccessibility and gut microbiota regulation in citrus pectin-naringin-zein complexes.

BACKGROUND: Understanding how food matrix interactions influence flavonoid digestion and gut microbiota modulation is essential for designing functional foods. This study investigated citrus pectin-naringin-zein ternary complexes, focusing on the effects of pectin modification (alkali treatment versus amidation) on naringin bioaccessibility and gut microbial regulation. RESULTS: Hydrophobic interactions dominated the formation of ternary complexes, while hydrogen bonding intensified during gastric digestion and weakened after intestinal digestion. Alkali-modified pectin-naringin-zein complexes significantly reduced naringin bioaccessibility by 3.4-11.2% compared with the corresponding low-methoxyl pectin-naringin-zein complexes during simulated digestion, suggesting improved protection against premature degradation and greater naringin retention during gastrointestinal digestion. In vitro fermentation demonstrated notable prebiotic potential, with selective enrichment of beneficial microbiota, particularly Bacteroidetes and Actinobacteria. Additionally, the ternary complexes markedly promoted short-chain fatty acid production, with acetic acid concentration reaching up to 16.50 mmol L-1, while valeric acid and branched-chain short-chain fatty acids (isobutyric and isovaleric acids) were also elevated. Among the formulations, the high-amidation/low-alkali modified pectin complex showed favorable overall performance in improving naringin stability and microbiota modulation, while different pectin modifications exhibited distinct advantages across bioaccessibility and microbiota-related parameters. CONCLUSION: These findings provide mechanistic insights into polysaccharide-protein-flavonoid interactions and offer a rational strategy for developing functional foods that improve flavonoid stability during digestion and promote gut health. © 2026 Society of Chemical Industry.