Process for the preparation of xanthohumol
The invention provides a process for the preparation of xanthohumol, wherein a xanthohumol-containing extract is mixed with water, a transition metal salt solution is added to the obtained mixture, and then the obtained xanthohumol precipitate is collected and dried to obtain xanthohumol of the purity higher than 90%.
1. A process for the preparation of xanthohumol, characterized in that:
a) a xanthohumol-containing extract is mixed with water;
b) a transition metal salt solution is added to the obtained mixture;
c) the obtained xanthohumol precipitate is collected and dried to obtain xanthohumol of the purity higher than 90%.
2. The process of claim 1 , characterized in that in step b) the concentration of the salt in the mixture is adjusted within the range of from 0.001M to 10M.
3. The process of claim 2 , characterized in that in step b) the concentration of the salt in the mixture is adjusted within the range of from 0.001M to 0.05M.
4. The process of claim 1 , characterized in that further after adding the salt in step b:
b1) the solution is alkalized to the pH level above 7;
b2) the first precipitate is filtered off, and the filtrate is acidified to the pH level below 7;
b3) the acidified filtrate is concentrated to obtain the xanthohumol precipitate.
5. The process of claim 4 , characterized in that in step b1) the solution is alkalized to the pH level in the range of from 7.5 to 10.5.
6. The process of claim 1 , characterized in that the xanthohumol-containing extract is obtained by extraction of post-extraction spent hops, hops, granulated hop plant or a mixture thereof with an organic water-miscible solvent, said solvent being used in an amount of from 0.1 to 10 liters per 1 kg of the raw material.
7. The process of claim 6 , characterized in that as an organic water-miscible solvent, ketones and alcohols or a mixture thereof are used.
8. The process of claim 7 , characterized in that as an organic water-miscible solvent, acetone, methanol, ethanol, propanol or a mixture thereof is used.
9. The process of claim 1 , characterized in that the extraction is conducted at a temperature in the range of from 5 to 65° C.
10. The process of claim 1 , characterized in that the xanthohumol-containing extract is mixed with water at a ratio in the range of from 0.1 to 5 liters of water per 1 liter of the extract.
11. The process of claim 10 , characterized in that the xanthohumol-containing extract is mixed with water at a ratio in the range of from 1 to 3 liters of water per 1 liter of the extract.
12. The process of claim 1 , characterized in that in step b) the concentration of a transition metal salt is provided within the range of from 0.01M to 0.05M.
13. The process of claim 1 , characterized in that as a transition metal salt, a copper(II) salt or a zinc(II) salt is used.
14. The process of claim 1 , characterized in that as a transition metal salt, a chloride salt, a nitrate salt, or a sulfate salt is used.
15. The process of claim 1 , characterized in that as a transition metal salt, copper(II) chloride, copper(II) sulfate or zinc(II) chloride or sulfate zinc (II) is used.