Blackening of olives by alkali treatment consists of acetic acid, sodium hydroxide and e.g. hydrochloric acid and iron salts treatment

摘要

The blackening of olives by alkali treatment comprises preliminary soaking in an aqueous solution of acetic acid for sodium hydroxide solution treatment at a depth of 0.5 metres above the olives, at 25 degrees C. The tank neutralises the product by means of carbon dioxide or hydrochloric acid and final addition of iron salts changes the colour.