Effect of salt concentration on free amino acid content and biogenic amines in the dried salted mackerel fishes during the processing and drying process

Understanding the influence of salt concentration and processing conditions on fish products is crucial for improving their quality, flavor, and safety, particularly in the context of salted and dried fish products. The study investigated the impact of varying salt concentrations and processing time on the composition of free amino acids (FAAs) and biogenic amines (BAs) during the processing of dried salted mackerel fish (Scomber japonicus), with the aim of assessing how these factors influence the quality, flavor, and safety of the product, in order to determine optimal processing conditions.The cleaned mackerel fish (Scomber japonicus) were soaked in sterilized saline solutions with salt concentrations of 50 g/L, 100 g/L, 150 g/L, and 200 g/L (w/v, fish to solution) at 25 degrees C for 30 minutes followed by drying in a temperature-controlled room (25 degrees C, ventilation speed 1 m/s) during the day and in a drying oven at night. The total FAA content peaked at 12000 mg/100 g in fish treated with 150 g/L brine at 204 h, with the flavor of glutamic acid also reaching its maximum level. This indicates that a 150 g/L salt concentration is beneficial for enhancing the flavor of salted fish. Furthermore, high salt concentrations inhibited the formation of BAs by suppressing bacterial activity and reducing precursor amino acids. The maximum total BA content was only 63.2 mg/100 g in fish treated with 200 g/L saline at 108 h, with the toxic histamine also minimized. These findings underscore the crucial role of salt in preserving the quality and safety of salted fish products. Redundancy Analysis further confirmed that salt concentration is a key factor in controlling the levels of amino acids and BAs during the processing of dried salted mackerel fish.