Effect of Broccoli Powder on the Physicochemical Properties, Nutritional Composition, and Antioxidant Activity of Unwashed Surimi from Litopenaeus vannamei

To enrich the gel properties and enhance the nutritional profile of unwashed Penaeus Vannamei surimi, this study integrated broccoli powder (BP) at varying concentrations (0, 2%, 4%, 6%, 8%, 10%) to create surimi gels. The impact of BP incorporation on the physicochemical properties, nutritional composition, and antioxidant activity of the surimi was thoroughly investigated. The results revealed a notable enhancement in the water-holding capacity, hardness, and gel strength of the surimi gels with increasing BP levels, reaching peak values at 10%. These improvements amounted to 27.78%, 59.88%, and 61.26%, respectively, compared to the base group. Sensory evaluation results indicated that the surimi gel with 6% BP achieved the highest overall sensory rating. Furthermore, the integration of BP notably improved short-term frozen storage stability of the surimi gels, as evidenced by a significantly smaller decrease in water-holding capacity and gel strength after frozen storage compared to the control group. Mechanistic analyses unveiled a significant increase in disulfide bond formation within the BP-added gels, a progressively denser microstructure, and a transformation in protein secondary structure from α-helix and random coil conformations to β-structure. Regarding nutritional enhancement, The addition of BP also led to significant increases in dietary fiber, vitamin C, and amino acid content, with a positive correlation observed with BP concentration. In vitro antioxidant assays showed that the scavenging rates for DPPH, ·OH, and ABTS⁺ radicals peaked at 10% BP addition, showing increases of 45.42%, 26.48%, and 36.39%, respectively, over the control. In summary, incorporating broccoli powder into unwashed Penaeus Vannamei surimi enhanced the gel properties while achieving a complementary reinforcement of plant and animal nutrients. This study provides a theoretical foundation for the value-added utilization of plant resources and the advancement of nutritionally balanced surimi products.