Freeze-denaturation mitigation in surimi by Naematelia aurantialba polysaccharides: structural stabilization and ice...

Hypophthalmichthys molitrix is highly appreciated by consumers for its rich nutritional content, tender texture, and affordability. However, surimi products derived from H. molitrix are prone to freezing denaturation during cryogenic storage, leading to a decline in quality. This issue has spurred widespread interest in the development of cryoprotectants. This study initially investigated the freeze-thaw stability, ice recrystallization inhibition activity, and cryoprotective effects of extracellular Naematelia aurantialba polysaccharides (NAPS) extracted from the fermentation broth. The results demonstrated that NAPS exhibits robust freeze-thaw stability and ice recrystallization inhibition capabilities, significantly enhancing the post-freeze-thaw viability of Lactobacillus plantarum and Saccharomyces cerevisiae. Further investigation focused on the impact of NAPS on the physicochemical properties of surimi gel stored at -20 °C for 30 days. Compared to the traditional commercial cryoprotectant (CA, composed of 4 % sucrose and 4 % sorbitol), the incorporation of NAPS significantly reduced cooking loss, enhanced water-holding capacity, and improved the strength, elasticity, and resilience of surimi gels. Additionally, the L* value and whiteness of surimi gels were correspondingly elevated. The chemical bonding forces within the surimi gel matrix were also augmented. Magnetic resonance imaging (MRI) analysis revealed that NAPS treatment resulted in more uniform water distribution and increased water retention in surimi gels, outperforming the CA group. Scanning electron microscopy (SEM) revealed that NAPS treatment produced a more compact surimi gel structure. This study underscores the potential value of NAPS as a cryoprotectant in the frozen surimi industry, offering significant advantages in enhancing the quality and stability of surimi during frozen storage.