Freeze–thawed characteristics of lactone tofu under the synergy of low‐frequency electrostatic field

Abstract The formation and melting of ice crystals bring undesirable changes to the gel structure of frozen food. To explore the role of Low‐frequency electrostatic field (LFE‐field) in the freeze–thaw quality of protein‐rich foods, the freezing temperature, thawing temperature, and the participation of the LFE‐field were used as variables to orthogonally optimize the treatment of tofu. The sensory score, color, moisture, aerobic bacterial count, and micromorphology were recorded to evaluate the quality variation of tofu. When be frozen at −50°C and thawed at 10°C, tofu maintains 91.1% hardness and 87.0% elasticity hinging on the effect of LFE‐field. When be frozen at −60°C in LFE‐field and thawed at 10°C, tofu maintains 90.7% hardness and 89.7% elasticity. The LFE‐field treatment also increased the water retention capacity and reduced the damage of ice crystals to the protein matrix structure of tofu. In addition, the LFE‐field has minimal impact influence on the tofu's color. Practical applications The low‐frequency electrostatic field (LFE‐field) treatment increased the water retention capacity and reduced the damage of ice crystals to the protein matrix structure of tofu during the freeze–thaw process. In the future, the small LFE‐field could easily be installed in refrigerator and used for long time freezing preservation protein rich food to extend its shelf life and improve the storage quality, such as cheese, tofu, etc.