How to Dry Red jujube/Dehydrate Red jujube in a Dehydrator

Jul 16, 2021

Introduction to red jujube：

The vitamin content of red jujube is very high. It is a temperate crop with strong adaptability and wide planting range. Red jujube has the characteristics of drought and waterlogging tolerance.

Red jujube drying process：

The core of red jujube processing is drying. The drying of red jujube is the process of internal water evaporation and sugar conversion on the premise of preserving the original quality of red jujube as much as possible. Red jujube is rich in sugar, which contains polysaccharide is a kind of substance without sweet taste. It must be transformed into monosaccharide under the action of biological enzyme to become sweet. This is the reason why red jujube ripens and becomes sweet. In order to make the sugar in red jujube fully transformed under the action of biological enzymes, it is necessary to enhance the activity of biological enzymes. Through long-term practice, we found the best temperature range of sugar conversion in jujube: about 60 ℃.
1. Heating stage
In the drying process, if the jujube fruit directly enters the high temperature environment suitable for sugar transformation, the huge temperature difference will cause the biological protection reaction of jujube, the epidermal cell pore will shrink, the crust will harden, and prevent the internal water evaporation of jujube. Therefore, in the early stage of jujube drying, full preheating and gradual heating are needed to prepare for a large amount of water evaporation. When the temperature of jujube reaches 45 ℃, it will feel a little hot. After 2-3 hours, wrinkles will appear when the jujube is pressed hard; When the temperature of jujube reaches 45 ℃ - 48 ℃, a layer of water droplets will appear on the surface of jujube.
2. Drying stage
In order to evaporate a large amount of free water inside the jujube, the temperature must be raised to 65 ℃ in the drying room within 3-5 hours. In order to facilitate a large amount of water evaporation, and pay attention to dehumidification, and keep the indoor temperature does not have a big change, in order to continuously evaporate water. When there are wrinkles on the surface of jujube fruit, it means that the drying is normal.
3. Dehumidification stage
When the temperature in jujube is uniform, the work can be completed in 6 hours. Because the moisture content of jujube is not much in the later period, we should pay special attention to the temperature control, not too much, 50 ℃ is better. At this time, the relative humidity also dropped down, such as higher than 60% can be slightly dehumidified. With the gradual balance of moisture in jujube, the purpose of drying is achieved. Then unload the dried sample in time.
Let it cool
The dried jujube must be ventilated and cooled before accumulation. If the jujube just unloaded from the drying room is piled up in the warehouse, because the jujube itself contains a lot of sugar, the sugar is easy to ferment and deteriorate under the action of heat, and the original pectin in the jujube will also decompose the pectin and pectin acid, which will inevitably make the jujube become a pool of mud, and the sugar in the jujube will also change, and there will be acid filaments, which will damage the jujube. Therefore, after drying, it must be cooled thoroughly before storage.

Recommendation of red jujube dryer/drying machine

Commercial 100-3000kg/h large amount of dehydration wide application and easy operation

Heat pump drying machine use the principle of inverse Carnot cycle. It absorbs low-temperature heat energy in the air, which becomes high-temperature heat energy after efficient heat collection and integration by the heat pump system, and is transported to the drying room for cyclic heating and drying of materials.It refers to exhausting the hot and humid air in the drying room directly to the outside of the drying room through dehumidification device, and then replenishing natural fresh air.

Hot air circle drying machine belongs to high temperature heat pump unit. Its working principle is: the working fluid of the heat pump is compressed by the compressor, becomes high temperature and high pressure gas, enters the condenser, condenses and liquefies the heat, and is used for air heating in the drying room. The moisture in the material is vaporized and evaporated by the form of hot air, and the evaporated water vapor is discharged by the moisture discharge system, thereby achieving the purpose of drying the drying material.