Synergistic effects of calcium chloride and intermittent freeze-thaw drying on the physicochemical and morphological properties of parboiled polished corn

The growing demand for convenience foods has shifted consumption patterns away from traditional corn-based dishes due to their lengthy preparation times. This study developed quick-cooking parboiled polished corn (PPC) by combining calcium chloride (CaCl 2 ) treatment and intermittent freeze–thaw drying. The process involved soaking in 0.25% CaCl₂, followed by freezing (− 20 °C) and drying (70 °C) cycles. The results revealed that the combination of CaCl 2 and intermittent freezing significantly reduced rehydration time from approximately 100 min to 17.64 min in glutinous corn and 20.28 min in yellow corn. Yellow corn treated with CaCl 2 and freezing exhibited the highest water absorption (357.33%) and volume expansion (333.33%), which correlated with a significant reduction in bulk density to 0.40 g/cm 3 . Scanning Electron Microscopy (SEM) analysis confirmed that the intermittent freeze-thaw drying process induced a macroporous architecture, with pore sizes reaching 77.95 μm in yellow corn, compared to only 8.64–11.88 μm in non-frozen samples. Importantly, these structural transformations occurred without altering the chemical functional groups of starch matrices. This study demonstrates that integrating CaCl 2 and freeze-thaw drying cycles provides an efficient method for producing high-porosity intermediate corn products, facilitating the rapid preparation of traditional foods in modern culinary contexts.