Lactiplantibacillus plantarum fermentation modulates gel network and protein conformation in pollock surimi:...

This study systematically investigated the effects of Lactiplantibacillus plantarum (LP) fermentation on the gelation properties and protein structure of pollock surimi. By modifying textural, rheological, and microstructural characteristics, as well as protein conformation, LP fermentation facilitated gel formation and improved swallowing safety, demonstrating its potential for producing surimi products suitable for individuals with dysphagia. Textural and rheological analyses indicated that LP fermentation significantly reduced gel elasticity and increased viscous behavior. Compared with the control (CK) group, which was not treated with LP, fermentation effectively decreased the free water content, suppressed protein degradation, and inhibited fatty acid oxidation in surimi. Microstructural observations further revealed that LP fermentation encouraged the development of a loose, porous gel network. Secondary structure analysis showed an increase in β-sheet content and a decrease in α-helix content after LP fermentation. Additionally, the LP group exhibited markedly stronger fluorescence intensity, higher total sulfhydryl content, and lower carbonyl levels, indicating effective mitigation of protein oxidation. According to the International Dysphagia Diet Standardization Initiative (IDDSI) framework, LP-fermented surimi gels met Level 6 standards for dysphagia-friendly foods, whereas the CK group did not comply with IDDSI criteria. In summary, LP fermentation induced a structural transition in myofibrillar proteins toward a β-sheet-rich conformation, leading to the formation of a porous gel network with tailored viscoelasticity and enhanced antioxidant capacity, ultimately ensuring safe swallowing performance.