中文摘要：

了解马铃薯组织在不同冷冻温度下的力学性能,对降低马铃薯组织在低温运输以及低温贮存过程中的力学损伤具有重要意义。首先应用低温拉伸系统测试了在不同环境温度下（室温和0、-3、-5、-8、-10、-15、-20℃）马铃薯组织的拉伸力学参数。结果表明随着温度的降低,弹性模量和抗拉强度都有所增大。当温度为-20℃时,弹性模量相比于常温值增大了10倍,而抗拉强度相比于常温值增加了2倍。然后应用低温成像系统观测了相应温度下马铃薯细胞的形态学参数。结果表明,除-20℃,马铃薯细胞的面积、长度、宽度以及周长均随着温度的降低而减小;当温度为-20℃时,这些参数略有增加。这是胞内冰晶形成并生长所致。由于在-20℃时液态水发生相变,造成马铃薯组织刚度增加,从而导致弹性模量和抗拉强度的急剧增加,这与宏观拉伸实验结果一致。

英文摘要：

To reduce the mechanical damage of potato tissues during low temperature transportation and storage, it is very important to understand the mechanical properties of the potato tissue under different freezing temperatures. Low temperature tension experiments were carried out. Potato tissue was tested at different temperatures（room temperature and 0,-3,-5,-8,-10,-15,-20 ℃）. The results show that the Young＇s modulus and tensile strength increase with the decrease of temperature. When the temperature was-20 ℃, the elastic modulus increased 10 times while the tensile strength increased 2 times compared to these values under normal temperature. Then, the morphological parameters of potato cells were observed under these temperatures. The results showed that the potato cell＇s area, length, width and perimeter decreased with the decrease of temperature except-20 ℃. When the temperature is-20 ℃, these parameters increased slightly. It is due to the formation of intracellular ice crystals and the growth of ice crystal. The liquid phase changes at-20 ℃, which cause the increases of the potato tissue stiffness and lead to a sharp increase in the Young＇s modulus and tensile strength. This is consistent with the results of the macroscopic tensile test.