Onion drying can effectively extend the shelf life of onions. Without an onion dryer machine or a belt dryer, The natural drying of onions in the sun will cause the onion skins to become hot and easy to necrosis, and the temperature is not controlled. If it is dried in the shade, it is easy to deteriorate, and the drying speed is very slow.
When a large number of onions need to be dried, like in the production of onion powder, it is recommended to use heat pump onion dryer equipment, and use medium and low-temperature hot air to dry, and onions can discharge the moisture in time. Dried onions will not change color and have a good effect on restoring moisture.
Onion drying process
1. Wash the onions, and pick out bad quality onions during the process of washing
2. Cut the onions and place them on the onion dryer tray evenly. Do not stack them too much, which will affect the drying effect.
3. Drying
- Temperature: Vegetables generally have a relatively high water content, so they need to be dried in low-temperature hot air. The high temperature will destroy the nutritional value of vegetables. The drying temperature of onions should NOT exceed 50 ℃, and the dehumidification rate during drying should reach more than 20%. Drying can be carried out in multiple stages. At first, the temperature is set to 50~40℃, then 40~30℃, and then down to about 35℃.
- Drying time: The drying cycle of a batch of onions is about 15 hours, and rapid drying will destroy the drying quality.
- Humidity: The moisture of onions contains a certain amount of sugar, making dehydration difficult. Controlling the dehydration speed is very important.
Traditional onion bulb drying and storage
To dry onions, spread them on a clean and dry surface with good ventilation, such as in a garage or shed. We should cure the onion for at least two to three weeks or until the upper neck is completely dry and the outer skin of the onion becomes slightly crispy.
