Effects of Static Magnetic Field Treatment on the Quality of Fresh-Cut Lotus Root During Storage

Static magnetic field (SMF) treatment is a new type of physical preservation method. In this study, SMF treatment was applied to fresh-cut lotus root to investigate its effects and possible mechanisms in terms of preserving color and maintaining freshness, with the goal of developing a preservation method for fresh-cut lotus root. Fresh-cut lotus root was treated with a magnetic field strength of 3 mt and stored for 14 days under cold conditions (temperature 4 °C, humidity 70%, wind speed 0.1–0.3 m/s, and no light). The control group received no SMF treatments. The effects of the SMF on the color, hardness, browning, weight loss, soluble solids content, vitamin C (Vit. C) content, and polyphenol content, as well as the activities of MDA, POD, PPO, and PAL and the contents of flavor substances of the fresh-cut lotus root were monitored every 2 days throughout the storage period. The results showed that the SMF treatment significantly slowed the decline in the sensory quality of fresh-cut lotus root (p < 0.05). After 6 days of storage, the degree of browning in the control group was 1.96 times that in the SMF group. The SMF treatment also significantly delayed reductions in the Vit. C and polyphenol contents in fresh-cut lotus root (p < 0.05). After 8 days of storage, the polyphenol content in the SMF group was 1.54 times that in the control group. After 12 days of storage, the Vit. C content of the SMF group was 1.45 times that of the control group. When the storage time reached 12 days, the L* and ΔE values of the control group were 1.89 times and 1.44 times those of the SMF group, respectively. The SMF treatment significantly reduced the activities of PPO and POD oxidases, as well as the MDA content (p < 0.05). After 12 days of storage, the activities of PPO and POD and the MDA content in the control group were 2.04 times, 1.42 times, and 1.71 times higher than those in the SMF group, respectively. After 14 days of storage, the weight loss rate in the control group was 1.65 times that in the SMF group, while the hardness of the SMF group was 1.23 times that of the control group. The SMF treatment increased the contents of esters, aldehydes, and ketones in fresh-cut lotus root compared with the control group. The contents of esters, aldehydes, and ketones in the SMF group were 1.04 times, 1.41 times, and 1.49 times higher than those in the control group, respectively. Moreover, using SMF treatment as a new preservation method for fresh-cut lotus root provides a promising strategy for preserving other fresh-cut fruits and vegetables.