冷冻储存对鸡蛋理化性质及微观结构的影响

本文通过测定pH、粘度、回弹高度和结构的变化，表征了置于-20 ℃下，储存不同的时间的新鲜鸡蛋的全蛋、蛋清、蛋黄、熟蛋及熟蛋黄的性质变化。实验结果表明：在-20 ℃下，新鲜鸡蛋随储存时间的增加，煮熟的全蛋回弹高度变小，熟蛋黄的回弹高度增大，从5 h到36 h，熟蛋黄的回弹高度从提高了2倍到4倍；蛋黄、蛋清和全蛋的pH值和粘度均发生了明显的变化，且pH的变化在储存10 h后更为显著；储存10 h的蛋清、蛋黄结构开始发生变化，蛋黄在冷冻24 h后质地变得较为平滑、紧密，可清楚表现为形成凝胶，到冷冻36 h后达到不可逆的变化。因此：在-20 ℃下，储存10 h，新鲜鸡蛋的品质已经由合格品下降为不合格的次品。

Effect of Frozen Storage on Physicochemical Properties and Microstructure of Eggs

Effect of different frozen storage time at -20 ℃ on whole egg, albumen, yolk, boiled egg and boiled yolk of fresh egg were investigated through determination of pH, viscosity, rebound height and structural change in the paper. The results showed that, at -20 ℃, the rebound height of boiled egg was decreased with increase of storage time of fresh eggs, while the bounce height of boiled yolk was increased 2-4 times after fozen-storaged from 5 to 36 h. Both pH and viscosity of egg yolk, albumin and whole egg had obviously changed with the increase of storage time, and the changes were more significant after freezing the samples for 10 h. The structures of the albumen and yolk frozen for 10 h began to change. After 24 h, yolk became smooth and tight, with gel, formed. And the change was irreversible after 36 h. Therefore, the quality of eggs can be greatly reduced to be substandard by frozen storage at -20 ℃for 10 h..