Process for refining glyceride oil comprising a basic quaternary ammonium salt treatment
The present invention relates to a process for refining glyceride oil comprising the steps of: (i) contacting glyceride oil with a liquid comprising a basic quaternary ammonium salt to form a treated glyceride oil; wherein the quaternary ammonium salt comprises a basic anion selected from hydroxide, alkoxide, alkylcarbonate, hydrogen carbonate, carbonate, serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate; and a quaternary ammonium cation; (ii) separating the treated glyceride oil from a salt comprising the quaternary ammonium cation; and (iii) subjecting the treated glyceride oil after the separation step to at least one further refining step; and to the use of contacting a glyceride oil with the basic quaternary ammonium salt for preventing or reducing the formation of fatty acid esters of chloropropanols and/or glycidol upon heating of the glyceride oil.
1. A process for refining glyceride oil comprising the steps of:
(i) contacting glyceride oil with a liquid comprising a basic quaternary ammonium salt to form a treated glyceride oil; wherein the basic quaternary ammonium salt comprises a basic anion selected from alkylcarbonate, hydrogen carbonate, and carbonate, and a quaternary ammonium cation;
(i) separating the treated glyceride oil from a salt comprising the quaternary ammonium cation after contacting the glyceride oil with the quaternary ammonium salt; and
(ii) subjecting the treated glyceride oil after the separation step to at least one further refining step.
2. The process of claim 1 , wherein the at least one further refining step is selected from: degumming, bleaching, winterization, depigmentation and deodorisation.
3. The process of claim 1 , wherein the at least one further refining step comprises a deodorisation step.
4. The process of claim 3 , wherein the deodorisation step involves steam stripping conducted at a temperature of from 160° C. to 270° C.
5. The process of claim 3 , wherein the deodorisation step involves steam stripping conducted at a temperature of from 160° C. to 240° C.
6. The process of claim 1 , further comprising at least one additional refining step of the glyceride oil conducted prior to the treatment with the basic quaternary ammonium salt in step (i), the at least one additional refining step being selected from bleaching and degumming.
7. The process of claim 6 , wherein the at least one additional refining step is a bleaching step with bleaching earth.
8. The process of claim 1 , wherein the at least one further refining step (iii) comprises a deodorisation step and the process does not comprise a step of degumming or bleaching.
9. The process of claim 1 , wherein the salt separated in step (ii) comprises chloride anions.
10. The process of claim 1 , wherein the salt separated in step (ii) comprises an anion of a free fatty acid.
11. The process of claim 1 , wherein the contacting step is conducted at a temperature of less than 80° C.
12. The process of claim 11 , wherein the contacting step is conducted at a temperature of from 35° C. to 55° C.
13. The process of claim 1 , wherein the quaternary ammonium cation is selected from:
[N(R a )(R b )(R c )(R d )] + ,
wherein R a , R b , R c and R d are each independently selected from C 1 to C 8 alkyl, wherein one or more of R a , R b , R c or R d may optionally be substituted at carbon atoms that are not bonded to the nitrogen atom by one to three groups selected from: C 1 to C 4 alkoxy, C 2 to C 8 alkoxyalkoxy, C 3 to C 6 cycloalkyl, OH, SH, CO 2 R e , and OC(O)R e , where R e is C 1 to C 6 alkyl.
14. The process of claim 13 , wherein R a , R b , R c and R d are each independently selected from C 1 to C 4 alkyl, wherein at least one of R a , R b , R c or R d is substituted each by a single —OH group.
15. The process of claim 13 , wherein the quaternary ammonium cation is choline: (CH 3 ) 3 N + CH 2 CH 2 OH.
16. The process of claim 1 , wherein the quaternary ammonium salt contacted in step (i) is choline bicarbonate: (CH 3 ) 3 N + CH 2 CH 2 OH HOCOO − .
17. The process of claim 1 , wherein the liquid comprising the basic quaternary ammonium salt comprises a solvent and the concentration of quaternary ammonium salt in the liquid is 15 wt. % to 90 wt. %.
18. The process of claim 17 , wherein the solvent is an aqueous solvent.
19. The process of claim 16 , wherein the liquid comprising the basic quaternary ammonium salt comprises an aqueous solvent and wherein the concentration of quaternary ammonium salt in the liquid is 50 wt. % to 90 wt. %.
20. The process of claim 15 , wherein the liquid comprising the basic quaternary ammonium salt comprises an aqueous solvent and wherein the concentration of quaternary ammonium salt in the liquid is 15 wt. % to 60 wt. %.
21. The process of claim 1 , wherein the glyceride oil is a vegetable oil.
22. The process of claim 21 , wherein the vegetable oil is selected from coconut oil, corn oil, cottonseed oil, groundnut oil, olive oil, palm oil, rapeseed oil, rice bran oil, safflower oil, soybean oil, sunflower oil, and mixtures thereof.
23. The process of claim 1 , wherein the glyceride oil is palm oil.
24. A method for preventing or reducing the formation of fatty acid esters of chloropropanols or glycidol upon heating of a glyceride oil, comprising contacting the glyceride oil with a basic quaternary ammonium salt, said basic quaternary ammonium salt comprising a basic anion selected from hydroxide, alkoxide, alkylcarbonate, hydrogen carbonate, carbonate, serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate; and a quaternary ammonium cation.
25. The method of claim 24 , wherein the contacting is carried out prior to heating the glyceride oil to a temperature of more than 100° C.
26. The method of claim 24 , wherein the glyceride oil is a vegetable oil selected from coconut oil, corn oil, cottonseed oil, groundnut oil, olive oil, palm oil, rapeseed oil, rice bran oil, safflower oil, soybean oil, sunflower oil, and mixtures thereof.
27. The method of claim 24 , wherein the glyceride oil is palm oil.
28. The method of claim 24 , wherein the quaternary ammonium cation is selected from:
[N(R a )(R b )(R c )(R d )] + ,
wherein R a , R b , R c and R d are each independently selected from C 1 to C 8 alkyl, wherein one or more of R a , R b , R c or R d may optionally be substituted at carbon atoms that are not bonded to the nitrogen atom by one to three groups selected from: C 1 to C 4 alkoxy, C 2 to C 8 alkoxyalkoxy, C 3 to C 6 cycloalkyl, OH, SH, CO 2 R e , and OC(O)R e , where R e is C 1 to C 6 alkyl.
29. The method of claim 28 , wherein R a , R b , R c and R d are each independently selected from C 1 to C 4 alkyl, wherein at least one of R a , R b , R c or R d is substituted each by a single —OH group.
30. The method of claim 28 , wherein the quaternary ammonium cation is choline: (CH 3 ) 3 N + CH 2 CH 2 OH.
31. The method of claim 24 , wherein the quaternary ammonium salt is choline bicarbonate: (CH 3 ) 3 N + CH 2 CH 2 OH HOCOO − .
32. The method of claim 24 , wherein the basic quaternary ammonium salt is choline hydroxide: (CH 3 ) 3 N + CH 2 CH 2 OH OH − .
33. A process for refining glyceride oil comprising the steps of:
(i) contacting glyceride oil with a liquid comprising a basic quaternary ammonium salt to form a treated glyceride oil; wherein the basic quaternary ammonium salt comprises a basic anion selected from hydroxide, alkoxide, serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate; and a quaternary ammonium cation;
(ii) separating the treated glyceride oil from a salt comprising the quaternary ammonium cation after contacting the glyceride oil with the quaternary ammonium salt wherein the salt separated comprises chloride anions; and
(iii) subjecting the treated glyceride oil after the separation step to at least one further refining step.
34. The process of claim 1 , wherein the at least one further refining step is selected from: degumming, bleaching, winterization, depigmentation and deodorisation.
35. The process of claim 1 , wherein the salt separated in step (ii) comprises an anion of a free fatty acid.