| 摘要 |
The extractive materials are extracted in counter-current, from a finally pulverized substance in an extractive phase with extraction solutions having different concentrations in a flat filtering bed extractor (2). In an additional cold extraction phase, the solution with the highest concentration obtained in the main extraction phase is further concentrated by passing it on the ground extraction substance (21). The extraction residue obtained in the additional extraction phase is finally pulverized (7) in presence of a high concentration extraction solution obtained in the main extraction phase. The main extraction phase is followed by a final extraction phase wherein the counter-current extraction is continued, after a previous heating (16) or after a prolonged resting period, by means of relatively low concentration solutions. This extraction method is essentially used to obtain highly flavoured extracts from natural aromatic substances such as coffee, and the cold extraction phase allows to obtain an improvement of the yield while preserving the aroma to its highest level.
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