Process for obtaining a tannin extract isolated from grapes, tannin extract obtained and uses thereof
AssigneeUniversitat De Lleida
InventorsBacardit Dalmases Anna, Ollé Otero Luis, Sorolla Casellas Sílvia, Casas Solé Concepció
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Abstract
A process for obtaining a tannin extract isolated from whole grape seeds is provided. The process is performed in as a one-pot reaction and in a single extraction step, wherein the seeds are processed without grinding or milling. Also provided is a tannin extract with improved antioxidant and light fastness properties obtained from whole grape seeds that includes a mixture of tannins and non-tannins, in which the content of tannins or polyphenols is higher than 50%. Ise, the tannin extract isolated from whole grape seeds can include a coloring agent.
Claims15
A tannin extract obtained by a method comprising:
- (a) adding an aqueous solution of a polyphenol-solubilizing agent to whole grape seeds without grinding or milling, wherein the polyphenol-solubilizing agent is selected from the group consisting of urea, sodium hydroxide, and a compound containing an SO3 group and is present at a concentration in the aqueous solution of 1-15% by weight with respect to the weight of the whole grape seeds;
- (b) reacting the aqueous solution of the polyphenol-solubilizing agent and the whole grape seeds at a pressure ranging between 2.5 and 3.5 atmospheres, and a temperature ranging between 100° C. and 160° C., in a period of time ranging from 1-2 hours in an autoclave reactor;
- and
- (c) recovering a liquid extract from the autoclave reactor,
- wherein the liquid extract comprises a mixture of pure hydrolysable tannins, pure condensed tannins that include procyanidins, and non-tannins that include gallic acid, and further wherein the liquid extract has a content of tannins or polyphenols that is greater than 50%.
A method of producing an aqueous liquid tannin extract comprising:
- (a) adding an aqueous solution of a polyphenol-solubilizing agent to whole grape seeds without grinding or milling, wherein the polyphenol-solubilizing agent is selected from the group consisting of urea, sodium hydroxide, and a compound containing an SO3 group and is present at a concentration in the aqueous solution of 1-15% by weight with respect to the weight of the whole grape seeds;
- (b) reacting the aqueous solution of the polyphenol-solubilizing agent and the whole grape seeds at a pressure ranging between 2.5 and 3.5 atmospheres, and a temperature ranging between 100° C. and 160° C., in a period of time ranging from 1-2 hours in an autoclave reactor;
- and
- (c) recovering a liquid extract from the autoclave reactor,
- wherein the liquid extract comprises a mixture of pure hydrolysable tannins, pure condensed tannins that include procyanidins, and non-tannins that include gallic acid, and further wherein the liquid extract has a content of tannins or polyphenols that is greater than 50%.
Dependencies are inferred from the claim text.