## 4 Discussion
So, if not accelerated by external factors, OLE hydrolysis will naturally occur along fruit ripening, which was showed for 'Galega Vulgar' from S3 forward, inducing a gradual increase on HT values. For 'Cobrancosa' this could not be observed since at harvest time (S6) OLE concentration was still showing an increasing trend, and also 'Cobrancosa' at S6 was still presenting a lower MI, when compared to 'Galega Vulgar' at the same period; therefore, it is possible that for 'Cobrancosa' at S6 stage olive fruits were yet not presenting signs of cellular tissue senescence. In regard to VERB, since its formation is metabolically linked to the conjugation of HT with caffe acid [38], the observed decrease of VERB concentrations along ripening is supported by the sequential HT increase. In fact, 'Galega Vulgar' registers it highest VERB levels at S3, the period when HT was registered as minimum (with no significant differences from S4). Previously, [PERSON] et al. [39] reported for 'Koroneiki' cultivar a correlation between the enhanced levels of VERB and the resistance of this cultivar towards _Verticillium dahlia_, a soil borne fungus responsible for _Verticillium_ wilt, a serious diseases affecting olive trees. Therefore, in conjugation with OLE degradation metabolites, the high VERB concentrations found in both cultivars also present significant relevance in the olive tree defensive mechanism. When compared to 'Galega Vulgar', 'Cobrancosa' registered a much different behavior, considering both MI and OPDW, which only reached considerably higher values at a latter ripening period (early December). As the results suggested, the maximum OPDW and OLE quantity should probably be achieved on a latter ripening, comparatively to 'Galega Vulgar', and hence, for 'Cobrancosa' cultivar, the harvesting time should be delayed in order to better evaluate the studied kinetics. Several studies have previously reported great changes in the phenolic profile during olive fruit maturation for different cultivars. [PERSON] et al. [40] showed for the Turkish 'Sarulak' cultivar, OLE concentrations ranging from 2981 to 375 mg/Kg, respectively, from an early-ripe to ripe stages. Regarding two other Turkish cultivars, [PERSON] et al. [41] showed the highest OLE content to be at an early ripening stage for 'Ayvalk' cultivar, with 210 mg/Kg, and at a latter ripening stage for 'Gemlik', with an average concentration of 147 mg/Kg. Regarding the Tunisian cultivar 'Chemlali', [PERSON] et al. [28] showed that higher OLE concentrations were registered during the early ripening stage, ranging from about 6500 mg/Kg to less than 1000 mg/Kg when full maturation was achieved. Different cultivars reveal specific and unique phenolic profiles that overcome a constant change during fruit ripening, as showed as well for the Portuguese cultivars 'Cobrancosa' and 'Galega Vulgar' with the present study. As VOO phenolic content is highly related to the presence and concentration of PCs in olive fruit, among other factors, such as \(\beta\)-glucosidaseide activity [11; 42; 43], the high OLE and VERB concentrations present on the studied cultivars represent a great potential for a standout nutritional quality VOO production. Results have demonstrated that for both 'Cobrancosa' and 'Galega Vulgar' different harvesting periods should be considered. In respect to studied variables, 'Cobrancosa' presented (within the total of 84 sampling days) the optimal harvest period at S6, when both MI and OPDW were at their maximum and OLE accumulation also showed an increasing trend. In contrast, 'Galega Vulgar' presented its optimal harvest period at S3, when the most significant MI increase was registered and also the highest OPDW was reached. At S3 'Galega Vulgar' also presented its highest OLE accumulation, as well as a considerably higher VERB concentration, which may predict a final VOO with a richer PCs fraction and improved nutritional value. Conceptualization, M.F.D. and F.M.R. ; Methodology, M.D.F., E.L., M.A., F.M.R. and M.F.D. ; Validation, M.F.D.