Involvement of Copper and Zinc Ions in Green Staining of Table Olives of the Variety Gordal.

The presence of metalochlorophyllic complexes of copper has been detected in table olives showing the alteration known as green staining. These compounds are absent in the healthy fruit. The possible implication of fungicidal treatment of olive trees in this alteration has been studied. No alteration was produced in table olives prepared with fruit from trees with and without fungicidal treatment and the differences found between copper levels in the fruit were not significant. The possibility that the copper involved in this alteration is of extraneous origin was, therefore, discarded. On the other hand, there were no significant differences in the levels of copper in random samples of fruits with and without green staining. Therefore, although the green-staining alteration is the result of the formation of complexes of copper with chlorophyll derivatives, it seems clear that the simple presence in the fruits of copper, by itself, does not lead to the appearance of green-staining.