Physicochemical conditions modulating the pigment profile in fresh fruit (Olea europaea Var. Gordal) and favoring interaction between oxidized chlorophylls and endogenous Cu.

The changes in allomerized chlorophyll during the growth and development of the olive fruit as well as during the main operations of its processing as green table olive (alkaline treatment and lactic fermentation) were investigated to study their influence in the color alteration known as green staining (GS). Chlorophyll synthesis coincided in time with the maximum content in allomerized intermediates, weeks before the fruits were harvested for processing. The alkaline treatment caused a subsequent chlorophyll oxidation independent of the high or low initial content of allomerized chlorophylls. However, this oxidation was directly related with the oxidizing capacity of the alkaline solution and the cell deterioration caused. The later maintenance of the fruits in osmotic solutions at different pHs that reproduce the pH reduction caused by the lactic fermentation showed that at pH below 4.5 the insertion of Cu into the chlorophyll molecule was produced in certain fruits; the extent of this reaction was greatest when the prior formation of oxidized chlorophylls exceeded 23%. This apparent relationship between chlorophyll oxidation and copper chlorophyll complexes was investigated in table olives with GS alteration.