The core of jujube processing is drying. The drying process of jujube is complete internal water evaporation and sugar conversion on the premise of preserving the original quality of the jujube as much as possible. Red jujube is rich in sugar, and the polysaccharide contained in them is a substance without sweetness. It must be converted into monosaccharides under the action of biological enzymes before it can be sweetened. This is the reason why red jujubes become sweet after ripening. It is necessary to fully convert the sugar in red jujubes under the action of biological enzymes, and it is necessary to enhance the activity of biological enzymes. Through long-term practice, we found the best temperature range for sugar conversion in red jujubes, that is around 60°C.
1 heating stage
During the drying process, if the jujube fruit directly enters a high temperature environment suitable for sugar conversion, the huge temperature difference will cause the jujube to undergo a biological protection reaction, the pores of the epidermal cells will shrink, the crust will harden, and the water inside the jujube will be prevented from evaporating. Therefore, in the early stage of drying red dates, it is necessary to fully preheat and gradually heat up to prepare for a large amount of water evaporation. Keep it at 45°C for 2-3 hours. When the temperature of the jujube reaches 45°C, it will be slightly hot. After 2-3 hours, wrinkles will appear on the body of the jujube when the jujube is pressed hard; A small layer of water droplets will appear.
2 drying stages
To make the free water in the jujube evaporate a lot, the temperature must be increased at this time, and the drying room should reach 65 ℃ within 3-5 hours. The temperature should not exceed 70 ℃. In order to facilitate the evaporation of a large amount of water, pay attention to dehumidification process and keep the indoor temperature from changing greatly, so as to continuously evaporate the water. When there are wrinkles on the surface of the jujube fruit, it means that the drying process is normal.