Method for separating off coloring components from aqueous plant extracts
View Patent ↗The invention relates to a method for separating off coloring components from aqueous plant extracts in which magnesium ions (Mg 2+ ) are added to the plant extract, at least one alkaline component is added to the plant extract, a precipitate is formed, and the precipitate formed is separated off from the plant extract.
1. A method for separating off coloring components from aqueous plant extracts comprising a) adding magnesium ions (Mg 2+ ) to the plant extract, b) adding at least one alkaline component to the plant extract, said alkaline component comprising hydroxide ions (OH − ) or, after combination with the plant extract forms hydroxide ion in the extract, c) forming a precipitate comprising magnesium hydroxide and off coloring components, and d) separating from the plant extract the precipitate formed.
2. The method of claim 1 , wherein steps a) and b) are carried out with stirring.
3. The method as of claim 1 , wherein the precipitate formed is separated off from the plant extract by sedimentation or filtration.
4. The method of claim 1 , wherein, in step a), a magnesium salt is added.
5. The method of claim 4 , wherein the magnesium salt is magnesium chloride, magnesium sulfate, magnesium acetate, or magnesium nitrate.
6. The method of claim 4 , wherein the magnesium salt is magnesium sulfate.
7. The method of claim 1 , wherein step a) is carried out at a temperature of 60-80° C.
8. The method of claim 1 , wherein the amount of alkaline component is selected in such as manner as to set a molar ratio OH — :Mg 2+ of 2.2:1-1.8:1.
9. The method of claim 1 , wherein the alkaline component is an aqueous solution or suspension of an alkali metal hydroxide or alkaline earth metal hydroxide.
10. The method of claim 9 , wherein the alkaline component is a suspension of calcium hydroxide.
11. The method of claim 1 , wherein the alkaline component is aqueous ammonia.
12. The method of claim 1 , wherein the alkaline component is an aqueous solution or suspension of a salt of a weakly organic acid.
13. The method of claim 1 , wherein the alkaline component is an amine.
14. The method of claim 13 , wherein the amine is ethylenediamine or triethanolamine.
15. The method of claim 1 , wherein the coloring components of the plant extract are tannins and/or flavonoids.
16. The method of claim 1 , wherein the plant extract is an artichoke extract.
17. The method of claim 16 , wherein the artichoke extract is an extract of artichoke roots.
18. The method of claim 1 , wherein step a) comprises adding an aqueous solution comprising dissolved magnesium ions.