Protein-glutaminase represses aggregate formation via electrostatic interactions between fish gelatin and carrageenan

Abstract

Although the physical properties of pork gelatin (PG) can be simulated by mixing fish gelatin (FG) and κ-carrageenan (KCG), these mixtures exhibit unacceptable turbidity under acidic conditions. In this study, we aimed to develop FG and KCG mixtures that simulate the visual and textural properties of PG using protein-glutaminase (PGase). Although FG and KCG mixtures were turbid, PGase-deamidated FG (DFG) and KCG mixtures were transparent similar to PG. Zeta-potential analysis revealed that PGase-deamidation decreased the positive charge intensities of FG, reducing DFG and KCG complex. For 6.67 % DFG + 0.4 % KCG gel, the texture profile analysis and breaking strength values were similar to 6.67 % PG gel, whereas the breaking strain was lower. These findings suggest that, except for ductility and brittleness, the visual and textural properties of PG could be simulated by combining PGase-catalyzed DFG and KCG.