炒蔬菜时,若中途需要加水,应该加入开水,加冷水会使蔬菜变硬,口感不好;再有,炒菜锅的温度突然下降,会使炒熟蔬菜的速度变慢,延长烹饪时间,导致营养降低;中途加冷水,还会使蔬菜中的纤维素不容易软化,老年人不易消化。制作蔬菜汤时,应将水煮沸后再放入蔬菜。蔬菜中含有丰富的维生素C,同时含有维生素C氧化酶(可氧化维生素C)。这种酶在50℃左右时活性最强,在100℃时会失去活性。若在冷水时就放入蔬菜,当水温升至50℃左右时,处于活化高峰的维生素C氧化酶可将维生有别 Fried vegetables, if you need to add water halfway, it should be added to boiled water, add cold water will make vegetables harden, taste is not good; Moreover, a sudden drop in the temperature of the wok will make fried vegetables slowed down, extending cooking time, resulting in Nutritional reduction; add cold water halfway, but also make the cellulose in vegetables is not easy to soften, the elderly are not easy to digest. When making vegetable soup, boil water and put it in vegetables. Vegetables are rich in vitamin C, also contains vitamin C oxidase (oxidizable vitamin C). This enzyme is most active at around 50 ° C and loses its activity at 100 ° C. If you put vegetables in cold water, when the water temperature rose to about 50 ℃, at the peak of activation of vitamin C oxidase will be able to survive