In the present study we propose to determine an approximate optimum harvesting period for table
olives and olive oil of two Portuguese olive cultivars (Madural and Verdeal Transmontana) based on
phenolic modifications (HPLC/DAD) and antioxidant activity (scavenging capacity on 2,2-diphenyl-1-
picrylhydrazyl and reducing power). Samples were collected from almost edibility to slightly overmature.
The sum of polyphenols, as well as its most abundant components oleuropein and hydroxytyrosol,
decreased during this maturation period, more intensively in Madural than Verdeal Transmontana.
In their green stages an antioxidant potential loss was gradually observed in both olive
cultivars, while in the latter purple-black phases a slight increase in the antioxidant activity was
observed. Both phenolic profile and antioxidant activity were highly correlated with the maturation
process. A principal component analysis showed the particular effect of maturation in both olive
cultivars.
Based on the acquired knowledge we can advance that, for these cultivars and geographical region,
olives harvest for table olives, traditionally collected sooner, can be performed in the middle of
September. For olive oil harvesting can occur in the first days of November, giving priority to cv. Madural
rather than Verdeal Transmontana, in order to enhance the bioactivity, phenolic composition and stability
of olive oils.
