# Comparative study on the in vitro digestive characteristics of surimi gels cross-linked by EGCG and/or TGase

## TL;DR

This study shows how combining EGCG and TGase affects the digestion of surimi gels, improving texture and peptide diversity while maintaining nutritional value.

## Contribution

The novel contribution is demonstrating the synergistic effect of EGCG and TGase on surimi gel digestion and peptide formation.

## Key findings

- EGCG/TGase cross-linking reduced digestibility by altering the gel network.
- Peptide diversity increased without affecting essential amino acid ratios.
- Digesta particle size decreased significantly during digestion phases.

## Abstract

This study examined the synergistic cross-linking effect of epigallocatechin gallate (EGCG) and transglutaminase (TGase) on the digestion characteristics of surimi gels via the INFOGEST in vitro digestion model. The digestibilities of the control, EGCG, TGase, and EGCG/TGase groups were 83.83, 82.54, 79.16, and 77.33%, respectively. The average particle size decreased from over 1000 μm in the oral phase to below 100 μm in the intestinal phase, and most proteins were degraded into peptides smaller than 15 kDa. The essential amino acid ratios (EAA/TAA ∼37.7, EAA/NEAA ∼60.5%) remained stable among all groups. EGCG/TGase synergistic cross-linking enhances texture, stabilizes digestibility, and enriches peptide diversity, showing great potential in the production of high-nutrition functional surimi products.

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•EGCG/TGase synergy reduced digestibility by network change, hindering enzyme access.•Digesta particle size and MW decreased during digestion and converged at the end.•EGCG/TGase increased peptide specificity without altering nutritional value.•Isopeptide band inhibited hydrolysis of peptide fragments in intestinal digestion.

EGCG/TGase synergy reduced digestibility by network change, hindering enzyme access.

Digesta particle size and MW decreased during digestion and converged at the end.

EGCG/TGase increased peptide specificity without altering nutritional value.

Isopeptide band inhibited hydrolysis of peptide fragments in intestinal digestion.