1、The initial moisture content of bitter gourd is about 90%, and the moisture content of dried bitter gourd slices is about 13%. The drying temperature of bitter gourd is suitable to set at medium and high temperature, and the temperature should not be too low or too high. If the temperature is too low, the drying speed will be slow. If the temperature is too high, it will have a great impact on the color, quality and nutritional components of bitter gourd, the structure will become hard, and the water rehydration will be poor too.
2、The effect of wind speed in the drying process is more important than that of temperature and thickness. The wind speed is preferably set at 1.9-2.4m/s. The appropriate wind speed can take away the moist air on the surface of the bitter gourd slices in time and accelerate the evaporation of water on the dry surface of the bitter gourd. When the wind speed is too low, the moisture removal force of bitter gourd slices is small, and the drying rate is also slow. If the wind speed is too high, most of the heat on the surface of the bitter gourd slices will be taken away by the airflow before it reaches the inside of the bitter gourd stem, which not only will hinder the drying speed, but also will causes heat loss.
3、The dehumidification and color fixation process is to ensure that the colorof the bitter gourdis natural green, that is, through the above-mentioned suitable temperature, wind speed, slice thickness, and effective use of heat energy to achieve the purpose of rapid dehumidification, dehydration and color fixation of bitter gourd slices. This is also helpful for avoiding color change or internal composition under inappropriate temperature and humidity parameters.