Antioxidant properties and release patterns of bioactive peptides from surimi gels with different degrees of cross-linking during dynamic simulated gastrointestinal digestion.

Protein cross-linking affects the gel properties and digestion behavior of surimi gels, but its effects on antioxidant activity and antioxidant peptide release during digestion remains unclear. This study investigated the effects of cross-linking degree on antioxidant activity, amino acid composition, and bioactive peptide release from surimi gels during dynamic gastric digestion (DG) and gastrointestinal digestion (DGI). Results showed that the control blank (CK) and low cross-linking degree (LCD) gels exhibited higher antioxidant activity at early digestion stages, whereas medium (MCD) and high cross-linking degree (HCD) gels displayed stronger antioxidant activity at later stages. The numbers of antioxidant peptides in MCD and HCD digests were 2.00- and 1.92-fold higher than those in LCD during DGI, respectively. Four antioxidant peptides were identified and validated, among which FYQM exhibited the strongest antioxidant activity. These results highlight cross-linking degree as a key regulator of digestion behavior and antioxidant potential in surimi gels.