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日常生活中,人们都有这样的经验:在滴水成冰的严冬,冻在室外的肉,时间一长表面会干;晾在绳子上的衣服,虽然冻得铁甲一样硬,但慢慢也会干……这种由固态的冰不经溶化成液态的水而直接变为气态的水蒸气的现象,物理学中称为升华。这一现象被用于食品工业,就出现了食品冻干技术。所不同的是,食品用制冷技术快速冷冻后,不是放在自然环境里慢慢干燥,而是放在真空环境中快速脱水干燥,从而制
In everyday life, people have the experience of dripping ice in the winter, frozen meat in the outdoor, the surface will be a long time to dry; clothes hanging on the rope, although the same as cold iron armor, but will slowly dry ... ... This phenomenon of solid-state ice that does not dissolve into liquid water but directly turns into gaseous water vapor is called sublimation in physics. This phenomenon is used in the food industry, there has been a freeze-dried food technology. The difference is that after the food is rapidly frozen by the refrigeration technology, the food is not dried slowly in the natural environment but quickly dehydrated and dried in a vacuum environment