Allicin, as a natural antibacterial active substance from plants, has great medical and health care value. However, due to its poor stability, its application in the field of food and medicine is limited. So, in this paper, allicin–zein–sodium caseinate composite nanoparticles (zein–Ali–SC) were prepared by antisolvent precipitation and electrostatic deposition. Through the analysis of the particle size, ζ-potential, encapsulation efficiency (EE), loading rate (LC) and microstructure, the optimum preparation conditions for composite nanoparticles were obtained. The mechanism of its formation was studied by fluorescence spectrum, Fourier infrared spectrum (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The stability study results showed that the particle size of composite nanoparticles was less than 200 nm and its PDI was less than 0.3 under different NaCl concentrations and heating conditions, showing good stability. When stored at 4 °C for 21 days, the retention rate of allicin reached 61.67%, which was 52.9% higher than that of free allicin. After freeze-drying and reheating, the nanoparticles showed good redispersibility; meanwhile, antioxidant experiments showed that, compared with free allicin, the nanoparticles had stronger scavenging ability of free radicals, which provided a new idea for improving the stability technology and bioavailability of bioactive compounds.

Allicin is a kind of natural antimicrobial active substance, but its water solubility is poor, and it is easy to degrade. In order to improve the stability and bioavailability of allicin, allicin–zein composite nanoparticles (Al-Ze) were prepared by the combination method of antisolvent precipitation and electrostatic deposition, and their characteristic parameters, such as average particle size, polydispersity index (PDI), and ζ-potential, were analyzed. Then, Al-Ze was used as the delivery carrier for the active substance (allicin), and gelatin with good film-forming properties was selected as the film-forming matrix to prepare Al-Ze gelatin films. The optical properties, mechanical properties, and characterization parameters were used to analyze the prepared composite materials; the results confirmed that Al-Ze gelatin film has good mechanical properties and barrier properties. The prepared film was applied to the storage of cold, fresh beef, and the quality change of beef was monitored at 4 °C. The results showed that Al-Ze gelatin film could effectively delay the quality deterioration of beef. This paper provides a new idea and data support for the application of Al-Ze gelatin film in meat storage and fresh-keeping, and offers new insight for the promotion and application of allicin in the food industry.

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.