Effect of Protamine on Microorganism Presence and Biogenic Amine Accumulation During Esox lucius Storage Under Refrigerated and Frozen Conditions

The Esox lucius is a high-quality fish species endemic to northern Xinjiang, having developed into a regional specialty industry with significant market value. However, during storage, it is prone to microbial growth that elevates biogenic amine levels, posing potential food safety risks. Therefore, this study systematically evaluated the effects of protamine—extracted from Esox lucius byproducts and used as a natural preservative—on the succession of microbial communities and biogenic amine accumulation in fish muscle under storage conditions of 4 °C, −3 °C, and −18 °C. A detection method for biogenic amines was also established. Results revealed characteristic changes in fish muscle microbial community α-diversity over storage time. Protamine treatment significantly delayed increases in total colony counts and microbial succession processes without altering the final dominant microbial community composition. By optimizing ultrasonic-assisted extraction and derivatization steps, an analytical method suitable for detecting eight biogenic amines in fish muscle matrices was established. Results indicate that protamine effectively inhibits the accumulation of all eight biogenic amines, with the 1% treatment group showing the most significant effect (p < 0.05). This study not only provides basis for the precise application of protamine in seafood preservation but also offers guidance for the resource utilization of aquatic by-products.