L-histidine-assisted ultrasound improved microstructure and gelation properties of reduced-salt surimi (Hypophthalmichthys molitrix) gel

In this study, the effect of several additives, including CaCl2, L-histidine (L-His) and sodium pyrophosphate, incorporation with ultrasound treatment on the gel properties of reduced-salt surimi, was tested. Among these additives and ultrasound treatment times, 0.1% L-His and 10-min ultrasound alone were determined to be more effective in increasing the gel strength, water-holding capacity (WHC) and reducing cooking loss (CL) of reduced-salt (1% NaCl) surimi gel. L-His and ultrasound alone or in combination could facilitate the transition of alpha-helix to beta-sheet and random coil, thereby increasing hydrophobic interactions and disulfide bonds in the gel. The results of low-field nuclear magnetic resonance showed that the proportion of immobilised water (PT22) in reduced-salt surimi gel was significantly increased (P < 0.05). The storage modulus (G ') of reduced-salt surimi gel was also increased. Moreover, scanning electron microscopy results showed that the gels treated with L-His and ultrasound alone or in combination had a more compact network structure. Notably, the synergy of L-His combined ultrasound treatment was the most effective in enhancing the characteristics of reduced-salt surimi gel.