This study investigated the impact of glycosylation modification on the structural and functional properties of soy protein isolate (SPI) and its ability to enhance the antibacterial and antioxidant performance of packaging films containing ginger essential oil (GEO). Four glycosylated protein conjugates (PGC1, PGC2, PGC3, and PGC4) were synthesized using glucose-induced glycosylation reactions at varying weight ratios (3:1, 2:1, 1:1, and 1:2). Glycosylation improved SPI's solubility, emulsifying activity, stability, water-holding capacity, and oil-holding capacity. These modified proteins were subsequently used to prepare active packaging films with 1 % (v/v) GEO. These composite films exhibited superior mechanical properties due to their compact structure, with tensile strength increasing by 37.46 % and elongation at break increasing by 77.72 %. When SPI glycosylation reached 38.23 % (PGC3), the composite film demonstrated a free radical scavenging rate of 91.04 % and effectively inhibited Escherichia coli and Pseudomonas aeruginosa, with inhibition zones of 15.52 mm and 14.71 mm, respectively. A 12-day low-temperature preservation experiment on grass carp confirmed the efficacy of GEO/PGC films in inhibiting spoilage and extending shelf life. Taken together, these results highlight the potential of glycosylation as a viable strategy to enhance protein-based packaging materials.

Keywords: Antibacterial; Antioxidant; Ginger essential oil; Glycosylation; Soy protein isolate.

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