Pulsed magnetic field-assisted cryogenic freezing of chestnuts: Effects on ice crystal dynamics, starch conversion and superior physicochemical properties.

In this experiment, chestnuts were frozen using a combination of low temperature and a pulsed magnetic field (PMF), and compared with several other common methods. The phase transition time for the PMF treatment group was approximately 80% shorter than control group and corresponded to minimal cellular tissue damage; the transverse relaxation time was significantly shortened, indicating a clear shift toward a bound water state. The PMF improved the physical properties of chestnut starch, and accelerated the conversion of starch into sugars and other components: soluble sugar and reducing sugar contents increased by 18% and 5%, relative to the control group, whereas starch content decreased to less than 10% of the control value. The total phenolic content of chestnuts was lower than control group, which could effectively inhibit browning. Overall, the combination of low temperature and pulsed magnetic field establishes an efficient, safe, and residue-free processing technology for chestnut preservation.