GB814574A - Method of producing ascorbic acid - Google Patents

Abstract

The invention comprises a method of obtaining pure ascorbic acid by extraction with a twophase system, in starting from natural materials containing ascorbic acid, characterized in that leaves from a plant of the type Tucca Guatemalensis or Fourcroya Gigantea are subjected to grinding in a screw press, after said leaves have been cut up in fragments transversely to the direction of the fibres, then the resulting ground product is pressed in a hammer grinder; the juice obtained is subsequently treated for extraction of the ascorbic acid by way of a solvent system comprising two non-miscible phases, each formed by water, acetone and magnesium chloride; the extract is concentrated and purified by a treatment with acetic acid, lastly pure ascorbic acid is recovered from said extract. In order to preserve the extracted juice, sodium hydrosulphite and xylol may be added in the preferred proportions of 7 g./l. of the former and 4 ccs./1. of the latter. The two phases obtained by extraction are opposed in counter-current apparatus, and after concentration the ascorbic acid is crystallized from the upper phase. Preferably the extraction is carried out in the temperature range 35-40 DEG C. Alternatively, instead of crystallizing immediately ascorbic acid, subsequent to the step of extraction with water-acetone-magnesium chloride system, the phase containing the extracted ascorbic acid is subjected to a concentration bringing the acetone content to 50/55 per cent with respect to the water present and the phase so concentrated is then subjected to a new extraction with a two system comprising water, acetone and zinc sulphate. The acetone which forms the lower phase extracts the ascorbic acid.