Mitigating fishy odor in surimi gels: Interactions between myofibril proteins and chito-oligosaccharides

This study investigated the impact of chito-oligosaccharides (COS) on the odor characteristics of surimi gels and the adsorption capacity of myofibril protein (MP) to aldehydes. Surimi gels with 1 wt% COS exhibited the freshest odor and the least fishy note. Adding COS significantly reduced the relative content of total volatile compounds by 95.28 μg/kg-148.57 μg/kg (0.5 wt%-2 wt%). The partition coefficient ( K a / b i o p o l ) of aldehydes in 6 mg/mL MP and 1 wt% COS simulated decreased by 2.38% compared to the water system. It demonstrated that the interaction between COS and MP inhibited the release of aldehydes. Additionally, the content of COS greatly influenced the conformation of MP. At concentrations of COS up to 1 wt%, COS filling within the surimi gels created a compact network structure, increasing disulfide bonds and decreasing water interstices. This facilitated COS-MP-aldehyde interactions, with hydrophobic interactions pivotal in adsorbing fishy odors. The smaller quenching constant (Ksv) in the MP-fishy odorant-COS (MP-F-COS) simulated system indicated that COS directly reacted with aldehydes. However, higher COS concentrations (1.5–2 wt%) led to irreversible deformation of MP after being compressed, with aldehydes being embedded and absorbed by the mucous membrane. The present work offers novel perspectives on mitigating off-odor emission in surimi products by applying COS.