The law of water loss in strawberries during solid osmotic dehydration (SSD) and liquid osmotic dehydration (LOD) was studied by low-field nuclear magnetic resonance (LF-NMR). Results showed that the moisture content of strawberries decreased gradually during the 72 h osmotic dehydration. At the end of the osmotic dehydration procedures, the moisture content of the strawberries treated with SSD and LOD decreased from 91.83% to 74.56% and 79.90%, respectively. The relaxation time T22 and T23 values modes decreased with the osmotic dehydration process in both two osmotic dehydration methods, indicating that both SSD and LOD reduced the fluidity of immobilized water and free water in strawberries. At the same time, the peak area A22 value gradually decreased, indicating that the two infiltration methods reduced the moisture content of the immobilized water. During the LOD, the free water peak area in strawberries showed a downward trend during the permeation process, but the decline was not significant (P>0.05). At the same time, the position of the T21 peak gradually shifted to the right, indicating that with the prolongation of LOD time, the fluidity of bound water in strawberries increased. While the peak area of free water in strawberries decreased significantly after 72 h of infiltration (P<0.05) in the SSD treatment and, compared with 0 h, the decrease range was 55.35%, and the fluidity of bound water in strawberries was weakened with the extension of osmotic dehydration time. In addition, a linear fitting model between the sum of peak integral areas of low field NMR (A21+A22+A23) and the moisture content of strawberries was established. The linear relationship was significant (P<0.05). R2 was greater than 0.90, and the fitting effect was great. This study explored the effects of SSD and LOD on strawberries from the perspective of moisture and provided a reference for the selection of osmotic dehydration methods in preserved strawberries production.
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