Enhanced gel properties of low-salt (1 %) silver carp surimi via combined starch addition and 915 MHz microwave pasteurization treatment

The optimization of gel properties in low-salt surimi is critical for producing high-quality, health-oriented products. The objective of this study was to reveal the combined effects of starch addition and 915 MHz microwave pasteurization treatment on the low-salt (1 %) silver carp surimi gel properties. Surimi samples with and without starch were processed using either microwave pasteurization or water bath, and water bath processed surimi without starch served as the control. Gel strength, texture, water-holding capacity (WHC), whiteness, water molecules distribution and mobility, protein secondary structure, and gel network were used to assess the gel properties and microstructure of the samples. Results demonstrated that microwave treatment and starch addition each improved gel properties, while their combination yielded the most significant enhancements. For surimi with starch treated by microwave, the gel strength increased by 93.50 % (406.93 g·cm to 787.42 g·cm), and WHC rose from 0.72 to 0.91, compared to controls. Additionally, this combination promoted ordered protein structure formation, which was characterized by increased β-sheet content to 60.92 % and decreased α-helix content to 10.74 %. These results indicated that microwave treatment and starch have a synergistic effect on improving the surimi gel properties. The alternative electric fields and faster heating rate of microwaves enhanced the starch-protein cross-linking and interaction forces, which contributed to the formation of a more compact and uniform microstructure. These results provided practical data for producing high-quality, low-salt surimi products.