Effect of freezing rate on water state in strawberry

Freezing can cause damage to the structure of fruit cells, resulting in quality loss of fruit. The changes of cell tissue and water state before and after freezing were investigated. After freezing at 1.57 ± 0.01 cm/h, the cellular structure of strawberry was severely damaged compared with freezing at 10.43 ± 0.35 cm/h, and the relative conductivity increased by about 40 % compared with the fresh. Moreover, the internal water of strawberries flows outward, and the strong binding water is obviously converted into free water with weak binding force. The proportion of free water in frozen samples increases by about 4 % compared with fresh samples, promoting a large amount of water loss. Meanwhile, the fractal dimension of frozen treatment groups increased by about 9 % compared with fresh samples. Therefore, from the perspective of water, high freezing rate treatment was beneficial to maintain strawberry quality.