鸭梨的冻结特征及影响因素分析

Research on Freezing Properties of Yali Pear and Influencing Factors

运用自制热镀锡膜铜—康铜热电偶测温方法测定了鸭梨果实不同部位的冻结曲线,对鸭梨果实与汁液的冻结特点作了比较,并对冰点温度与部分品质参数的关系进行了探讨。试验结果表明,鸭梨果实的冻结曲线有3种形式,典型的形式具有过冷点、初始冰点、平衡冰点、终止冰点等关键特征点;果实不同部位的过冷点和冰点温度及其出现的时间顺序存在差异,越靠近果心,冻结速率越小,冰点温度越高;果实与果汁冻结特征的不同点在于果实有"特征小段"而果汁没有,且果汁较果实容易冻结;在一定范围内,鸭梨果实冰点温度与可溶性固形物含量呈极显著负相关,而与单果重、硬度相关性不显著。

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 soMie 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.