Oxidized cellulose nanofibrils-based surimi gel enhancing additives: Interactions, performance and mechanisms

Surimi-based products with preferred textural properties and high nutritional value are fashionable throughout the market. Enhancing surimi gel characteristics is of key importance for enabling the following processing and warranting the end-product quality, but challenging due to the lack of energy- and performance-efficient processes and the elusive mechanisms underpinned such enhancements. Focusing on enhancing surimi gel properties by introducing sustainable additives, we successfully explore functionalized cellulose nanofibrils as a textural enhancer in surimi gels and establish a new model to expound the interaction mechanisms. Firstly, TEMPO-mediated oxidation prior to homogenization harvests functionalized cellulose nanofibrils with unique fibrillary shape, uniform nano-size, high surface hydrophilicity and activated -COO - groups, highly suited for the additive use in surimi gels (Monto et al., 2021). Secondly, the innovative application of oxidized cellulose nanofibrils at a remarkably low concentrations (0.1 g/100 g surimi) greatly improve the whiteness, microstructure, water holding capacity, gel strength and thermal stability of the surimi gels, through a synergistic effect of matrix-reinforcing, water binding and entrapping, covalent interactions (disulfide bonds, amide bonds), non-covalent interactions (hydrogen bonds, ionic bonds) and favorable protein conformational changes within the network. Next, a new mechanism model toward the high-performance surimi gels is concluded to better elucidate the interactions between oxidized cellulose nanofibrils and myosin molecules. We expect that this work can provide guidelines on designing novel and high-quality cellulose-additive foods and understanding the roles of food additives in meat gel systems, for advancing the applications of new additives and gelation mechanisms in the food industry. • A low cellulose nanofibrils (TCN) addition (0.1%) greatly improves surimi gel properties. • Deliberately activated COO − groups at TCN surface facilitates cellulose-myosin interactions. • Improved water holding capacity due to surface hydrophicility, water binding and entrapping. • Enhanced gel strength due to newly introduced ionic bonds, hydrogen bonds and physical entanglement. • A new mechanism model illustrating cellulose-protein interactions is established.