Property changes of tilapia (Oreochromis mossambicus) gelatin of low bloom value in response to a chemical modification using laccase and tea polyphenols

Lower Bloom value of gelatin will cause insufficient gel strength. Both laccase and tea polyphenols were explored in this study to modify Bloom value, structure, and other properties of tilapia gelatin with low Bloom value (70.3 g). Using the selected conditions, two modified products thus prepared had higher Bloom values (90.1 and 112.5 g). Meanwhile, the results revealed that the two modified products were conjugated and crosslinked by tea polyphenols <i>via</i> four key reaction steps, contained protein aggregates of higher molecular weights, and had typical triple-helix and more ordered secondary structure. Compared with tilapia gelatin, the two modified products had reduced <i>in vitro</i> digestibility, decreased surface hydrophobicity, enlarged gelling and melting temperatures, larger particle sizes and zeta-potentials, and enhanced foaming properties. Moreover, higher increase of Bloom value of tilapia gelatin consistently caused much changes in these assessed properties. Collectively, this crosslinking strategy is applicable in valorizing gelatin quality and value.