Decaffeination of aqueous extracts
AssigneeGeneral Foods Corporation
InventorsRavi Prasad, Martin Gottesman, Robert A. Scarella
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Abstract
Aqueous extracts of roasted coffee are stripped of aroma, concentrated and thereafter decaffeinated by means of contact with a decaffeinating fluid such as liquid or supercritical carbon dioxide. Aroma loss is minimized by using water to remove caffeine and aroma from the CO.sub.2 stream, recovering aromatics from this caffeine-containing aqueous stream and adding-back these aromatics to the decaffeinated extract. Preferably equipment cost is minimized by use of a single pressure vessel to transfer the caffeine from the extract stream to the CO.sub.2 and from the CO.sub.2 to the water stream.
Claims4
A method of decaffeinating an aqueous caffeine-containing extract of roasted coffee comprising the steps of:
- (a) subjecting the extract to a stripping operation in order to remove volatiles and from about 5 to 15% by weight of the extract,
- (b) condensing the extract strippings of step (a);
- (c) evaporatively concentrating the stripped extract to a solids concentration between 30% and 50% by weight;
- (d) condensing the aqueous evaporate of step (c),
- (e) continuously contacting the concentrated extract in a countercurrent fashion with a decaffeinating fluid at a temperature between 10.degree. C. and 180.degree. C. and a pressure between 50 to 450 atmospheres, said fluid being either a liquid gas or a supercritical fluid at the conditions at which the decaffeination operation is effected;
- (f) thereafter, contacting the caffeine-containing fluid from step (e) with an aqueous stream containing the condensed evaporate of step (d), at a temperature between 10.degree. C. and 180.degree. C. and a pressure between 50 to 450 atmospheres in order to decaffeinate said fluid;
- (g) passing the decaffeinated extract of step (e) and the caffeine-containing aqueous stream from step (f) to vent tanks and condensing volatiles exiting the vent tanks;
- (h) removing caffeine from the aqueous stream of step (f) and combining at least a portion of this decaffeinated liquid with the condensed evaporate of step (d) to form the aqueous stream of step (f);
- (i) adding condensed strippings from step (b) and condensed volatiles from step (g) back to the decaffeinated extract resulting from step (e).
Dependencies are inferred from the claim text.