Method for obtaining a vineyard pigment for technical applications

摘要

It is described a method in which a crushed pomaces is washed with demineralized water to reach pH 4.5 to 5.0. The first leaching is carried out with sodium hydroxide solution with a concentration of 0.1 to 0.15 mol / l at a temperature of 20 - 22 ø C for 6 - 7 days, the mixture is further provided by HCl at pH 2.0 - 2.5, follow washing out colouring and accompanying substances in a special filter with distilled water until pH 5.0 to 5.5 and then 60% solution of isopropyl alcohol and then with distilled water again, so the special filter is not exchanged. Follow washing with 1% ammonium hydroxide solution, the solution is separated from the residues of raw material. Further is carried out a second leaching of the raw material with sodium hydroxide at a concentration of 0.25 - 0.5 mol / l at 50 - 60 ø C for 8 - 10 hours and the extract is separated. Following sedimentation by HCl at pH 2.0 - 2.5, washing the sediments with distilled water until pH 5.5 - 6.0 and decantation and dissolving of sediment again in ammonium hydroxide solution and evaporation to a concentration of 4 to 5% of dry matter in aqueous solution.