Preparation and application of bioadhesive hydrogel powder loaded with quorum sensing inhibitor isomaltitol for salmon preservation

Salmon is susceptible to spoilage and single cold storage is insufficient for effectively extending its shelf life. The objective of this study was to investigate the impact of hydrogel powder loaded with isomaltitol on the shelf life of salmon. Rheological analysis of the hydrogel revealed that its G' consistently exceeded G'', without any crossover point, indicating gradual gelatinization and the formation of an elastic solid. In conjunction with Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results, the peaks at 3398 cm⁻¹ for gelatin and 3446 cm⁻¹ for sodium alginate were observed in GSDH-2 and showed a shift. The characteristic peak at 2997 cm⁻¹ for isomaltitol was not present in GSDH-2, but was observed in the spectrum of GSIH-2 and became more prominent. These results suggest successful hydrogel preparation. Thermogravimetric analysis (TGA) results showed that the hydrogel lost only 13 % at 200°C. Scanning electron microscopy (SEM) analysis revealed a three-dimensional network and distinct void structure in the hydrogel, indicating its suitability for practical applications, resistance to volatilization, ability to encapsulate drugs, and ability to swell when in contact with water. The preservation experiment showed that the TVB-N value in the control group reached 15 mg/100 g on the third day, while the GSIP treatment group reached this value on the ninth day. Additionally, the TBA value in the GSIP treatment group decreased by 67.2 % under the same storage duration, and the degradation of myofibrillar protein was inhibited by 60.6 %, extending the shelf life of salmon by one week. This finding confirms the potential of hydrogel loaded with isomaltitol as a new preservation method.