The Application of L-Arginine in Improving the Quality of Low-Salt Fish Ball Gel

The gel quality of fish balls is a core indicator determining their texture, water-holding capacity, elasticity, and processing stability. However, low-salt processes (usually referring to sodium chloride addition below 1.5%) lead to reduced solubility and weakened cross-linking ability of myofibrillar proteins in surimi, which in turn causes defects such as insufficient gel strength, easy breakage, and increased juice loss rate. As a natural basic amino acid, L-arginine can specifically address the gel quality defects of low-salt fish balls by regulating protein interaction behavior and optimizing the gel network structure. Its specific application mechanisms and effects can be analyzed from the following aspects:

I. Promoting Solubility and Cross-Linking of Myofibrillar Proteins to Enhance Gel Strength and Elasticity

In a low-salt environment, myofibrillar proteins (such as actin and myosin) in surimi tend to aggregate rather than dissolve due to reduced ionic strength and weakened electrostatic repulsion on the molecular surface. This makes it difficult for proteins to form a uniform and dense three-dimensional network structure during subsequent heat-induced gelation. The final consequences include low gel strength (insufficient chewiness), poor elasticity (weak recoverability after compression) of fish balls, and even breakage during steaming or boiling.

L-arginine can improve this problem through two key pathways: On one hand, it enhances the solubility of myofibrillar proteins. Polar groups (e.g., guanidine group, amino group) in the L-arginine molecule can form hydrogen bonds and electrostatic interactions with water molecules and polar residues (e.g., carboxyl group, hydroxyl group) of proteins, breaking the aggregation forces between protein molecules. Meanwhile, its basic property can adjust the pH value of the surimi system to a range close to the optimal solubility interval of myofibrillar proteins (far from the isoelectric point; the isoelectric point of surimi protein is usually around 5.0), increasing the net charge on the protein molecular surface and further promoting protein solubility, thereby providing sufficient "molecular raw materials" for gel network construction. On the other hand, L-arginine promotes protein cross-linking. Dissolved myofibrillar proteins form cross-links through hydrophobic interactions and disulfide bonds during heating. L-arginine can stabilize the active groups (e.g., sulfhydryl group) of proteins, reducing the ineffective loss of groups during heating; at the same time, its molecular structure can act as a "bridge" to assist the binding between protein molecules, ultimately forming a denser and more elastic gel network. In practical applications, adding 0.3%-0.8% L-arginine to low-salt fish balls (with 1.0% sodium chloride added) can increase the gel strength by 20%-40% and the elastic recovery rate by 15%-25%, significantly improving the chewiness and texture of fish balls.

II. Optimizing Water-Holding Capacity of the Gel Network to Reduce Juice Loss Rate

Another core problem of low-salt fish balls is poor water-holding capacity. Due to the loose gel network with large pores, juice loss easily occurs during heating or storage, which not only makes the fish balls dry in texture but also causes the loss of nutrients. The essence of this phenomenon is that the protein gel network in a low-salt environment cannot effectively trap water molecules, and water tends to seep out from the network pores.

L-arginine can optimize the water-holding capacity of the gel network from the structural level: First, by promoting proteins to form a dense three-dimensional network, it reduces large pores in the network, making it more difficult for water molecules to seep out through the pores. Second, the L-arginine molecule itself has strong hydrophilicity and can form a "hydration layer" by binding to water molecules, and fix this bound water in the gel network, reducing the proportion of free water. Third, its effect of regulating pH value can further enhance the hydration capacity of proteins—when the system pH is far from the protein isoelectric point, the charge density on the protein molecular surface increases, and the adsorption capacity for water molecules is enhanced, further improving the water-holding capacity of the gel. For example, after adding L-arginine to low-salt products such as cod fish balls and hairtail fish balls, the juice loss rate can be reduced from 15%-20% to 8%-12%, making the fish balls fuller and juicier in texture; at the same time, it can reduce thaw loss during frozen storage and extend the product shelf life.

III. Improving Sensory Quality and Processing Adaptability of Low-Salt Fish Balls

The low-salt process not only affects the gel functional properties of fish balls but may also cause problems such as bland flavor, dull color, and easy deformation during processing. L-arginine can simultaneously optimize these sensory and processing attributes through multiple effects.

In terms of flavor and texture, L-arginine itself has no unpleasant odor and can reduce the loss of flavor substances by improving the gel structure; at the same time, its effect of promoting protein solubility and cross-linking can make the fish balls have a more delicate and elastic texture, avoiding the common problems of "looseness" and "dryness" in low-salt products. In terms of color, the basic property of L-arginine can inhibit the oxidation of myoglobin in surimi (reducing the formation of metmyoglobin) and stabilize the binding between proteins and pigments, allowing the fish balls to maintain a bright milky white or light pink color and enhancing their appearance appeal. In terms of processing adaptability, low-salt surimi added with L-arginine has better viscosity and formability, and is less likely to break or deform during processing links such as extrusion, forming, and steaming, reducing the defective rate during production. It is especially suitable for industrialized continuous production lines of fish balls.

IV. Aligning with Clean Label Trends to Enhance Product Safety and Health Attributes

Traditional low-salt fish balls often rely on chemical modifiers such as phosphates and carrageenan to improve gel quality. However, some consumers have concerns about chemical additives, and excessive phosphates may increase the metabolic burden on the kidneys. As a semi-essential amino acid for the human body, L-arginine not only has high safety (complying with the GB 2760 National Food Safety Standard for the Use of Food Additives) but also can provide additional amino acid nutrition for products, meeting consumers' demand for "natural, healthy, and clean-label" products. Under the current trend of healthy food consumption, using L-arginine to replace some chemical modifiers in the production of low-salt fish balls can significantly enhance the market competitiveness of products while balancing both quality and health attributes.