Magnetic field-assisted immersion freezing preserves starch structure and quality of fresh waxy corn puree.

To improve the frozen quality of fresh waxy corn puree, this study evaluated magnetic field-assisted immersion freezing (MIF) at 5, 10, and 20 mT, compared with slow freezing (AF), air blast freezing (CF), and immersion freezing (IF). The effects on quality attributes and starch multi-scale structure were assessed, and the underlying mechanism was elucidated. Results showed that MIF at 5 mT (MIF-5) improved freezing kinetics, reducing phase transition time by 40.32% compared with IF, while enhancing the retention of total phenolics and flavonoids and minimizing color and texture degradation. Starch structure analysis revealed that MIF-5 increased relative crystallinity and short-range molecular order while better preserving granule integrity. This preservation inhibited water migration and molecular rearrangement upon thawing, maintaining macroscopic quality. In conclusion, MIF-5 is identified as an effective technology for improving frozen quality of waxy corn puree, providing a theoretical basis for applying MIF in high-moisture native starch-based foods.