Double-crosslinked effect of TGase and EGCG on myofibrillar proteins gel based on physicochemical properties and molecular docking.

The aim of this study was to determine the influence and mechanism of combining EGCG with TGase on properties of myofibrillar protein (MP) gel. A double-crosslinked effect was observed when EGCG and TGase were added into MP gel. Breaking force, deformation, water holding capacity and hardness of double-crosslinked MP gel increased by 25.3 ± 3.0 g, 0.5 ± 0.3 mm, 1.76 ± 0.4% and 34.11 ± 2.56 g, compared with those of TGase induced gel. Light microscopy and low-field nuclear magnetic resonance results indicated with EGCG content increasing, pores and structure of double-crosslinked gels became smaller and denser, T22 decreased from 266.162 ms to 252.845 ms and its proportion increased from 94.103% to 96.956%. Molecular docking illustrated covalent and non-covalent interactions between EGCG and myosin heavy chain Ⅱ A, and confirmed TGase catalytic mechanism with myosin heavy chain Ⅱ A as substrate. Therefore the mixture of EGCG and TGase could be used as novel cross-linker in surimi.