The mechanism of L-Arginine promoting sodium migration in low-salt foods

The mechanism by which L-Arginine promotes sodium migration in low-sodium foods is mainly related to ion competition and changes in protein structure.

Research by the team led by Professor Gao Ruichang from the School of Food and Biological Engineering, Jiangsu University, has shown that during the preparation of low-sodium fish balls, L-Arginine competes with Na⁺ through a "nest-occupying" effect. Its partial substitution causes Na⁺ to gradually migrate during the preparation process of fish balls: the Na⁺ concentration inside the fish balls decreases, while the concentration outside increases. For example, after adding L-Arginine to low-sodium fish balls (containing 0.3% NaCl), the internal Na⁺ concentration of the fish balls decreases from 34.38 mg/L to 30.37 mg/L, and the external Na⁺ concentration increases from 25.78 mg/L to 29.80 mg/L.

On one hand, the partial substitution of Na⁺ by L-Arginine reduces the loss of Cl⁻ and promotes Cl⁻ to exert an electrostatic shielding effect. On the other hand, it can promote the transformation of the secondary structure of myofibrillar protein from α-helix to other secondary structures, which is conducive to the increase of disulfide bonds and the exposure of hydrophobic groups. These changes provide more favorable conditions for the subsequent aggregation and cross-linking of protein molecules, thereby forming a dense three-dimensional gel network structure and improving the quality of low-sodium fish balls.

In addition, the promotion of Na⁺ migration by L-Arginine may also be related to its own chemical structure. As an amino acid with amino and carboxyl groups, it has a certain degree of polarity and charge, and can compete with Na⁺ for binding sites on protein molecules. This prompts Na⁺ to be released from the protein binding sites, thereby undergoing migration.