一般认为喷雾干燥条件“苛刻”时,高温气体可能对热敏感生物活性物质不利。事实上,喷雾液滴及干燥粉末的温度远远低于进气温度,这是因为液滴中的水汽化,造成“冷却”效应,阻止被干燥物料温度升至液体的汽化温度之上。在干燥的最后阶段,水分较少时,温度可能升高,但亦低于出口气 It is generally believed that when the spray-drying conditions are “harsh”, the hot gas may be detrimental to the heat-sensitive bioactive substances. In fact, the temperature of the sprayed droplets and the dried powder is much lower than the temperature of the intake air because the water in the droplets is vaporized, causing a “cooling” effect, preventing the temperature of the dried material from rising above the vaporization temperature of the liquid. In the final stages of drying, the temperature may increase when the water content is low, but also lower than the outlet gas