Method for preparing raw pollen
The present invention relates to a method for preparing raw pollen which is suitable for being used for the preparation of allergen extracts. The method involves instantaneously freezing the pollen immediately after harvesting, optionally followed by drying the frozen pollen by sublimation.
1. A method for preparing raw pollen, comprising the steps of:
harvesting pollen with equipment which takes the pollen off of the plants while in the ground, and
flash freezing the harvested pollen in a period of time following its harvesting such that the pollen does not begin to agglomerate, to obtain frozen pollen powder.
2. A method according to claim 1 , wherein the flash freezing of the harvested pollen is carried out by exposing the pollen to a temperature less than or equal to −20° C.
3. A method according to claim 1 , wherein the flash freezing of the harvested pollen is carried out using dry ice or liquid nitrogen.
4. A method according to claim 1 , wherein the harvesting step comprises engaging the pollen containing plants by the use of a motorized chassis which has suction heads which communicate through suction ducts with a separation cyclone and a suction fan and which includes a recovery hopper, and wherein the step of freezing the harvested pollen takes place while the harvested pollen is in the recovery hopper.
5. A method according to claim 1 , wherein the pollen is grass pollen, herbaceous plant pollen or tree pollen.
6. A method according to claim 1 , further comprising the step of drying the frozen pollen by sublimation.
7. A method according to claim 6 , wherein the step of drying the frozen pollen continues until the pollen has a water activity of less than 0.35 Aw.
8. A method according to claim 6 , wherein the drying by sublimation is carried out at the freezing temperature of the pollen.
9. A method according to claim 6 , wherein the drying by sublimation is carried out at a temperature less than or equal to −20° C.
10. A method according to claim 6 , wherein the drying by sublimation is carried out at a pressure less than or equal to 70 Pa.
11. A method according to claim 6 , wherein the drying by sublimation is carried out at a temperature of between −20° C. and −50° C., at a pressure of between 40 and 60 Pa.
12. A method for preparing raw pollen, comprising the steps of:
harvesting the pollen with equipment which takes the pollen off of plants while in the ground, and
immediately as the pollen is harvested, flash freezing the harvested pollen in order to obtain frozen pollen powder.
13. A method according to claim 12 , wherein the flash freezing of the harvested pollen is carried out by exposing the pollen to a temperature less than or equal to −20° C.
14. A method according to claim 12 , wherein the flash freezing of the harvested pollen is carried out using dry ice or liquid nitrogen.
15. A method according to claim 12 , wherein the harvesting step comprises engaging the pollen containing plants by the use of a motorized chassis which has suction heads which communicate through suction ducts with a separation cyclone and a suction fan and which includes a recovery hopper, and wherein the step of freezing the harvested pollen takes place while the harvested pollen is in the recovery hopper.
16. A method according to claim 12 , wherein the pollen is grass pollen, herbaceous plant pollen or tree pollen.
17. A method according to claim 12 , further comprising the step of drying the frozen pollen by sublimation.
18. A method according to claim 17 , wherein the step of drying the frozen pollen continues until the pollen has a water activity of less than 0.35 Aw.
19. A method according to claim 18 , wherein the drying by sublimation is carried out at the freezing temperature of the pollen.
20. A method according to claim 18 , wherein the drying by sublimation is carried out at a temperature less than or equal to −20° C.