Process for extracting polyphenolic antioxidants from purine-containing plants

Abstract

The present invention is directed to a process for isolating polyphenolic antioxidants from purine-containing plant material, comprising the steps of: (a) extracting the plant material with a hydroxylic extracting liquid preferably at low temperature; (b) selectively adsorbing the extract obtained in step (a), preferably at low temperature; and (c) desorbing the adsorbed material with a hydroxylic desorbing liquid, preferably at relatively high temperature. The process is especially suitable for producing cocoa antioxidants for use in pharmaceutical, cosmetic and nutritional compositions.

What is claimed is:  
     
         1 . A process for isolating polyphenolic antioxidants from purine-containing plant material, comprising: 
 (a) extracting the plant material with a hydroxylic extracting liquid;    (b) selectively adsorbing the extract obtained in step (a) on a solid adsorbent which has a high polyphenol/purine adsorption selectivity; and    (c) desorbing the adsorbed material with a hydroxylic desorbing liquid.    
     
     
         2 . A process according to  claim 1 , in which the desorbed material is concentrated and optionally dried.  
     
     
         3 . A process according to  claim 1 , in which the adsorbent comprises polyvinylpolypyrrolidone or a chemical or physical modification thereof.  
     
     
         4 . A process according to any one of the preceding claims, in which the adsorbent comprises chitosan or a chemical or physical modification thereof.  
     
     
         5 . A process according to any one of the preceding claims, in which step (a) is carried out at a temperature below 50° C., preferably between 0 and 30° C.  
     
     
         6 . A process according to any one of the preceding claims, in which step (b) is carried out at a temperature below 30° C.  
     
     
         7 . A process according to any one of the preceding claims, in which step (c) is carried out at a temperature above 30° C., preferably between 50 and 110° C.  
     
     
         8 . A process according to any one of the preceding claims, in which the hydroxylic extracting liquid in step (a) comprises water.  
     
     
         9 . A process according to any one of the preceding claims, in which the hydroxylic desorbing liquid in step (c) comprises water and a lower alcohol or water and a lower ketone.  
     
     
         10 . A process according to any one of the preceding claims, in which said purine-containing plant material is cocoa, coffee or tea, especially cocoa.  
     
     
         11 . A water-soluble antioxidant composition obtainable using the process of any one of claims  1 - 10 , which is free of chlorinated hydrocarbons and substantially fat-free, and which contains at least 15% by weight in total of catechin, epicatechin and/or chlorogenic acid, less than 5% by weight of purine components, less than 0.5% by weight of caffeine and has a TEAC value of at least 0.4.  
     
     
         12 . A composition according to  claim 11 , which contains at least 20% by weight in total of catechin and epicatechin, and/or has a TEAC value of at least 0.6.  
     
     
         13 . A composition according to  claim 11  or  12 , which contains at least 25% by weight in total of catechin and epicatechin and/or less than 0.4% by weight of caffeine and/or less than 3% by weight of theobromine, and/or has a TEAC value of at least 0.8.  
     
     
         14 . A nutritional, pharmaceutical or cosmetic composition containing an antioxidant composition according to any one of claims  11 - 13 .