Improving the Quality of Low-Salt Beef Myofibrillar Protein Gels with L-Lysine and Konjac Glucomannan: Water...

Reducing sodium in meat products is nutritionally desirable, but salt reduction often weakens myofibrillar protein gelation and reduces texture quality and water retention. This study investigated the effects of L-lysine (Lys) and konjac glucomannan (KGM) on the physicochemical properties, gel characteristics, and structural changes of beef myofibrillar protein (MP) gels under low-salt conditions. The results indicated that reducing NaCl from 0.6 to 0.2 M decreased water-holding capacity (WHC), increased cooking loss, and produced a loose gel network. Compared with the 0.2 M NaCl group, the combined Lys-KGM treatment increased WHC from 28.53% to 56.70% and reduced cooking loss to 22.19% (p < 0.05). Texture analysis showed that Lys-KGM increased hardness and springiness by 69.40% and 80.43%, respectively (p < 0.05). LF-NMR indicated a higher proportion of immobilized water and reduced water mobility in the combined treatment. Lys increased reactive sulfhydryl content and surface hydrophobicity, whereas KGM reduced surface hydrophobicity and enhanced water immobilization. Lys-KGM slightly but significantly decreased α-helix and increased β-sheet contents (p < 0.05), accompanied by changes in the relative contributions of intermolecular forces and a more continuous gel network. Molecular docking and molecular dynamics simulations provided supporting evidence for different interaction patterns between myosin and Lys/KGM. These results suggested that Lys and KGM might help maintain the quality of low-salt meat protein gels and provide a formulation basis for reduced-sodium meat products.