Xuzhou Xinbaisheng Protective Equipnent Co., Ltd. , https://www.xinparkson.com
Three methods for marinating aquatic products
The pickling process for fish can be carried out using several methods, each with its own advantages and disadvantages. One of the most traditional techniques is dry pickling. In this method, a suitable amount of salt is directly rubbed onto the surface of the fish. After salting, the fish are stacked on a marinating shelf or placed in layers within a container, with salt evenly sprinkled between each layer. Over time, the salt causes the fish to release moisture, forming brine that helps the salt penetrate into the flesh through diffusion. However, since the initial salt penetration is slow due to the gradual release of tissue fluids, the overall pickling time tends to be longer. Dry pickling is effective in dehydrating the fish meat and doesn’t require special equipment, but it can lead to uneven salt distribution if not done carefully. Additionally, the exposure to air during the process may cause fat oxidation, resulting in an undesirable "oil burning" effect.
Another common method is wet pickling, where the fish is fully submerged in a salt solution. This method is typically carried out in containers like barrels or tanks, and the fish may be soaked and marinated once or twice. Wet pickling allows for more uniform salt distribution because the entire fish is in contact with the brine. Since the fish remains sealed away from the air, fat oxidation is minimized, which helps preserve the flavor and appearance of the final product. However, one downside is that excessive dehydration often occurs, leading to a drier texture. Also, the salt concentration inside the fish rarely reaches saturation, limiting long-term preservation potential.
A third approach is the mixed pickling method, which combines both dry and wet techniques. The fish is first coated with salt and left in a dry pile before being placed in a container with additional salt layers. A heavy stone is used to press the fish, encouraging the release of juices that dissolve the surrounding salt into a saturated solution. Once this happens, a portion of saturated brine is added to maintain the solution’s strength as the fish continues to absorb salt. This method ensures even salt penetration, prevents early spoilage, and reduces the risk of fat oxidation, resulting in a better-quality product.
Regardless of the method used, the quality of the salt plays a crucial role in the effectiveness of the pickling process. High-quality salt should contain at least 90% sodium chloride, preferably 95–97%. Impurities such as magnesium sulfate, calcium sulfate, and trace metals like iron and copper can negatively affect the outcome. For example, high levels of calcium and magnesium salts can slow down salt absorption, increasing the risk of bacterial growth and spoilage. When these impurities exceed 5%, the texture of the fish becomes tough and unappealing, and the color may turn gray or chalky. Even small amounts of iron (30 mg/kg) or copper (0.2–0.4 mg/kg) can cause discoloration, turning the fish brown or yellow.
Additionally, the particle size of the salt influences the pickling process. Fine salt dissolves quickly but may clump, leading to uneven distribution. Coarse salt, especially when larger than 7 mm, reduces the contact area between salt and fish, slowing down the absorption process and potentially causing uneven salting or spoilage. Based on practical experience, a salt particle size of 4.5–6.4 mm is considered ideal for consistent and effective pickling.