Abstract: To retard the retrogradation of starch gel foods and enhance their quality, this study investigated the effect of magnetic field on the retrogradation characteristics of wheat starch gel. Changes in hardness, gel strength, water loss rate, water distribution, retrogradation degree, crystalline structure, short-range order, and microstructure were determined during the storage of starch gel. The results indicated that the magnetic field significantly inhibited the retrogradation of starch gels, and this inhibitory effect was positively correlated with magnetic field intensity. On the 8th day of storage, compared with the control group (0 mT), the hardness, gel strength, and retrogradation degree of the starch gel treated with 15 mT magnetic field were reduced by 26.38%, 23.12%, and 65.57%, respectively. These results demonstrate that the magnetic field effectively suppresses the retrogradation of starch gels. Meanwhile, the magnetic field significantly reduced the water loss rate of starch gel, and inhibited the transformation of strongly bound water into free water in the gel. This indicated that the magnetic field enhanced the water retention capacity of starch gel during storage, and maintained the water distribution in the system. Moreover, on the 8th day of storage, as the magnetic field intensity increased from 0 to 15 mT, the relative crystallinity of the starch gel decreased from 32.95% to 27.39%, and the degree of short-range order decreased from 0.906 to 0.824. This indicated that the magnetic field inhibited the ordered rearrangement of starch molecules during storage, thereby delaying the retrogradation of starch gels. This study offers a promising new approach for the quality control and shelf-life extension of starch gel foods during storage.

Key words: magnetic field; wheat starch gel; retrogradation characteristics; structural analysis