Effects of magnetic field-assisted freezing on the freeze-drying characteristics and quality of pectin-sucrose cryogels.

BACKGROUND

The physical quality of freeze-dried food products is defined by their porous morphology. To enable efficient regulation of the physical quality of fruits and vegetables, pectin-sucrose cryogels were selected as a model system. Cryogels frozen under varying magnetic field conditions were subsequently freeze-dried, and their drying characteristics, microstructure, texture, and rehydration properties were analyzed.

RESULTS

A vacuum freeze-dried pectin cryogel system was developed to simulate the natural network structure of fruits and vegetables. The results showed that magnetic field-assisted freezing led to the formation of a small and lamellar pore structure in cryogels. Additionally, the drying time for samples frozen at -20 °C and subjected to a 10 mT magnetic field was comparable to the control group with no magnetic field, but the rehydration rate was higher (10.37 g g). Correlation analysis showed that magnetic field strength had a significantly negative correlation with drying rate, number of peaks, maximal force, and positive area (P < 0.05), and a significantly positive correlation with rehydration rate (P < 0.05).

CONCLUSION

Magnetic field-assisted freezing produced small lamellar porous structures, which enhanced the product's rehydration and texture quality. © 2025 Society of Chemical Industry.