In the test, made possible by the European Agricultural Fund for Rural Development, batches of planting onions and planting shallots were heated to 40 and 42 degrees in a short heating period. A heater that uses the residual heat from the mechanical cooling was used for this. Drying was done with the shutters closed. This kept the air humidity level.
Bejo seeds tested the samples for head rot in their laboratory. When heated to 32 degrees the infestation halved. With a heat treatment of up to 42 degrees the infestation was reduced to 4%. Higher temperatures produce better results. However, using 40 or 42 degrees increases the risk of damage and isn't ready for everyday use. More research is planned into this.
The lower temperature of 30 to 32 degrees also gives a large reduction in head rot. Practical tests at other companies show that this way of drying is simple. They heated to 30 to 32 degrees. Because they worked with propane heaters here, they used an air ventilation level of 10-15%. The onions were at the right temperature within a day. There was a lot of energy in the parties and the onions still dried in warm and damp weather. There was no wear or infestation with black fungus. They no longer needed a heater later on. This reduced the use of gas.
In short, this heat treatment method can be used in practice and is energy efficient. In one treatment the onions were dried and diseases were fought.
For more information:
DLV
Harrie Versluis
T: 0031 (0) 6 – 22 93 00 47
E: h.versluis@dlv.nl
Bejo seeds tested the samples for head rot in their laboratory. When heated to 32 degrees the infestation halved. With a heat treatment of up to 42 degrees the infestation was reduced to 4%. Higher temperatures produce better results. However, using 40 or 42 degrees increases the risk of damage and isn't ready for everyday use. More research is planned into this.
The lower temperature of 30 to 32 degrees also gives a large reduction in head rot. Practical tests at other companies show that this way of drying is simple. They heated to 30 to 32 degrees. Because they worked with propane heaters here, they used an air ventilation level of 10-15%. The onions were at the right temperature within a day. There was a lot of energy in the parties and the onions still dried in warm and damp weather. There was no wear or infestation with black fungus. They no longer needed a heater later on. This reduced the use of gas.
In short, this heat treatment method can be used in practice and is energy efficient. In one treatment the onions were dried and diseases were fought.
For more information:
DLV
Harrie Versluis
T: 0031 (0) 6 – 22 93 00 47
E: h.versluis@dlv.nl