Investigation of the enhancement mechanism of ethanol addition on the gel performance of heat-induced surimi

This study investigated the mechanism of ethanol enhancing the gel properties of heat-induced silver carp (Hypophthalmichthys molitrix) surimi gels. The presence of ethanol reduced the thermal stability of surimi protein, and the denaturation temperature of myosin decreased by approximately 7 degrees C in the presence of 5% ethanol. The gel strength, textural characteristics, and storage modulus (G ') of the gels improved depending on ethanol levels, while the water holding capacity (WHC) remained steady. Adding ethanol stabilized the alpha-helix and beta-sheet in the protein structures of the gels, reducing the content of the random coil. Appropriate heat denaturation rate induced by ethanol increased protein cross-linking, which may relate to forming more disulfide bonds. In addition, ethanol incorporation promoted the formation of more isopeptide bonds catalyzed by transglutaminase (TGase) and weakened the hydrolysis of surimi proteins by cathepsins, further enhancing the formation of a dense and uniform gel network.