A method for optimising the green colour in green table olives which comprises: - treatment of the green table olives with at least one zinc salt selected from among zinc acetate, zinc bisglycinate, zinc chloride, zinc citrate, zinc gluconate, zinc lactate, zinc oxide, zinc carbonate, zinc sulphate or combinations thereof; - treatment of the green table olives from the previous step with a buffered base solution selected from among a buffered solution of borate, tris(hydroxymethyl)aminomethane, glycine, phosphate or carbonate or combinations thereof; and - heat treatment for preservation, wherein: - the green table olives are subjected to a treatment with a buffered acid solution selected from among acetic acid, ascorbic acid, benzoic acid, citric acid, lactic acid, malic acid, propionic acid, succinic acid or combinations thereof that takes place before the treatment with the buffered base solution, - the treatment with the buffered acid solution consists of putting the green table olives in contact with the solution having a concentration equal to or greater than 0.1M, in a solid/liquid ratio equal to or greater than 1:1 (w/v), for a period of time comprised between 1 minute and 10 days, and at a temperature between 15°C and 90°C, - the treatment with the zinc salt consists of putting the green table olives in contact with a solution of the zinc salt having a concentration comprised between 0.005 and 3 g/L, in a solid/liquid ratio equal to or greater than 1:1 (w/v), for a period of time comprised between 5 minutes and 1 year, and at a temperature between 15°C and 129°C, - the treatment with the buffered base solution consists of putting the green table olives in contact with the solution having a concentration equal to or greater than 0.1M, in a solid/liquid ratio equal to or greater than 1:1 (w/v), for a period of time comprised between 5 minutes and 1 year, and at a temperature between 15°C and 129°C, and - the heat treatment for preservation is sterilisation for 15 F 0, at a temperature between 117°C and 129°C or the heat treatment for preservation is pasteurisation at 80°C, for a time between 6 and 14 minutes. - treatment of the green table olives with at least one zinc salt selected from among zinc acetate, zinc bisglycinate, zinc chloride, zinc citrate, zinc gluconate, zinc lactate, zinc oxide, zinc carbonate, zinc sulphate or combinations thereof; - treatment of the green table olives from the previous step with a buffered base solution selected from among a buffered solution of borate, tris(hydroxymethyl)aminomethane, glycine, phosphate or carbonate or combinations thereof; and - heat treatment for preservation, - the green table olives are subjected to a treatment with a buffered acid solution selected from among acetic acid, ascorbic acid, benzoic acid, citric acid, lactic acid, malic acid, propionic acid, succinic acid or combinations thereof that takes place before the treatment with the buffered base solution, - the treatment with the buffered acid solution consists of putting the green table olives in contact with the solution having a concentration equal to or greater than 0.1M, in a solid/liquid ratio equal to or greater than 1:1 (w/v), for a period of time comprised between 1 minute and 10 days, and at a temperature between 15°C and 90°C, - the treatment with the zinc salt consists of putting the green table olives in contact with a solution of the zinc salt having a concentration comprised between 0.005 and 3 g/L, in a solid/liquid ratio equal to or greater than 1:1 (w/v), for a period of time comprised between 5 minutes and 1 year, and at a temperature between 15°C and 129°C, - the treatment with the buffered base solution consists of putting the green table olives in contact with the solution having a concentration equal to or greater than 0.1M, in a solid/liquid ratio equal to or greater than 1:1 (w/v), for a period of time comprised between 5 minutes and 1 year, and at a temperature between 15°C and 129°C, and - the heat treatment for preservation is sterilisation for 15 F 0, at a temperature between 117°C and 129°C or the heat treatment for preservation is pasteurisation at 80°C, for a time between 6 and 14 minutes.