EFFECT OF PH ON THE COLOR FORMED BY FE-PHENOLIC COMPLEXES IN RIPE OLIVES

The effects of the pH in the flesh of ripe olives processed for table olive production, the type of acid used to correct it, the heating pro cess used and the iron content of the flesh on the colour of the final product were studied. The best colour was obtained by bottling the fr uits at pH 7. Additions of acids, especially citric acid, always cause d discoloration when olives were bottled at a pH of around 7. On the o ther hand, when the fruits were packed at a pH higher than 7 the addit ion of certain amounts of acids produced darker olives. Darker colours are related to higher iron contents in the flesh, but treatment of ol ives with ferrous gluconate before neutralising the pH of the flesh yi elded better colours than those treated after neutralising for the sam e iron concentration in the olives. Results obtained after adding iron to the oxidation solutions did not show the same pattern as those obt ained using fruits. These results suggest that the fixation of the col our formed is not only due to the phenol-iron complexes.