Research on Freezing Properties of Yali Pear and Influencing Factors

Hot tinning of copper-constantan thermocouples were used to determine the freezing curve of different parts of Yali pear fruit,to make a distinction on freezing characteristics between fruit and juice,and to research the relationship between some quality parameters of Yali pear and freezing point temperature. The results indicated that there were three shapes on freezing curve of Yali pear,and superrcooling point,initial freezing point,equilibrium point and final freezing point were included in the typical shape. There was difference in the temperature of superrcooling point and freezing point as well as the time of their appearance between different parts of the fruit,and the closer the distance to the core of fruit was,the lower rate of freezing and the higher freezing point temperature. The small section appeared in fruit but not in juice,and it was easier to freeze of fruit juice than fruit. In a certain range,the freezing point temperature was significantly negatively correlated with the soluble solid content,but no correlation with weight and hardness of single fruit.