Static magnetic field-assisted freezing of sea buckthorn pulp: intensity-window effects and efficiency-quality trade-offs

Frozen sea buckthorn pulp is an important raw material for further processing, and optimizing the freezing process is essential for preserving product quality and nutrients. This study evaluated the effects of static magnetic field (SMF)-assisted freezing (3–6 mT) on freezing behavior and quality by combining COMSOL simulations with CRITIC analysis. SMF treatment showed an intensity-dependent window effect on freezing: treatments at 3–4 mT accelerated freezing, whereas those at 5–6 mT reduced freezing efficiency. The 3 mT treatment shortened the freezing time by 41.2% (to 120.3 min) and increased SOD activity by 76.64%. The 4 mT treatment increased total phenolic content and l -ascorbic acid content by 6.23% and 11.11%, respectively, and yielded the highest DPPH radical-scavenging activity (76.68%) and FRAP value (1.49 μmol/mL). CRITIC analysis identified the 4 mT treatment as optimal, with the highest comprehensive score (0.64), indicating its superior balance between freezing efficiency and quality preservation.