What is the basic principle of dried chilies? What does it have to do with?

Begin to evaporate, the first surface of the free water evaporation, and evaporation speed, when the pepper water loss to 50%~60%, evaporation speed began to become smaller, at this time the pepper water inside and outside the formation of water potential, the pepper internal water diffusion (transfer), that is, by the water parts (internal) to the pepper surface transfer - evaporation transfer - evaporation until dry. The water in pepper is divided into free water and colloidal bonded water. Most of it is free water, and only a small part is colloidal bonded water. Free water's binding force is small, easy to evaporate, colloidal binding water binding force is strong, evaporation is slower.

(1) The influence of temperature on the drying speed and quality: in the drying process, if the relative humidity of the drying medium is unchanged, the higher the temperature, the greater the water vapor pressure difference between the pepper and the drying medium, the faster the evaporation and loss of water in the pepper. Conversely, the lower the temperature of the drying medium, the slower the pepper dries. But when the temperature is too high (a long time above 90°C high temperature), although the water evaporation speed of pepper is accelerated, it will make the pepper with very high water content suddenly meet the hot and dry air, the cells are easy to be destroyed, the contents are lost, the cells and the juice in the cells are rapidly vaporized and expanded, and the sugar and other organic substances are often turned into a coking state due to high temperature, or the decomposition of the loss. Make the pepper "black pepper", become waste. Or in high temperature and low humidity under the formation of "hard shell pepper", hinder the water diffusion. If the drying time is short, the formation of "bubble pepper", that is, often said "skin in the raw".

(2) The influence of humidity on the drying speed: in the drying process, if the temperature of the drying medium is unchanged, the lower the relative humidity is, the greater the saturation difference of water vapor in the medium is, and the faster the drying speed is. If you raise the temperature and lower the relative humidity (by letting out the air), the water in the peppers evaporates more easily and dries faster. For example, at the late drying stage, when the temperature is 60°C and the relative humidity is 30%, the water content of pepper is 8%. When the temperature is constant and the relative humidity is 8%~10%, the water content of pepper can be reduced to 1.5%. If the relative humidity is kept at 30% and the temperature is raised from 60°C to 70°C, the water content of the peppers can be reduced from 8% to 4%.

(3) The influence of air flow speed on drying speed and quality: if the temperature is unchanged and the air does not flow, the relative humidity of the air will reach saturation and the evaporation will stop. At this point, the saturated water vapor will be removed and replaced with dry air, so that drying and evaporation can continue. Excluding moisture, air flow has a great effect on the drying speed. Therefore, continuously accelerating the air flow and diffusion speed can maintain a higher water vapor pressure difference between the pepper and the air medium, accelerate the pepper drying speed, shorten the drying time and cycle. But the air flow speed is too large, the use of heat energy is not economical. In the early 1980s, our country used intensive drying oven which can make air flow, which can speed up the drying process, as well as economic utilization of heat energy. In recent years, a built-in dryer has been promoted to speed up the air flow in the drying room. The drying of chili peppers is to reduce the water content of fresh peppers to about 16 percent, raising the concentration of soluble solids to the point where it is difficult for living things to live on and use them. At the same time, the enzyme activity in pepper body was inhibited to achieve the purpose of long-term preservation and utilization.