Effect of freezing rate on some structural parameters of carrot cells

In order to study the effect of different freezing rates on the cell structure of fruits and vegetables, the carrot tissue samples were selected and frozen under different freezing rates respectively. For both of the blanched and fresh carrot tissue, the relationship between the freezing temperatures and the freezing rates was studied. A cylindrical model for plant cell was established. With this model, the cell volume, turgor pressure and permeability coefficients were calculated. The results showed that the freezing temperatures of the blanched carrots were lower than that of the fresh ones, and the freezing temperatures decreased with the increase of the freezing rates, the cell volume decreased as the turgor pressure rose, and the development tendency of the volume increased at first, then decreased when the temperature dropped. As for the permeability coefficient, it decreased with prolonged freezing process and its changing amplitude also decreased as the freezing rates increased.