## 4 Discussion  
'Galega Vulgar' and 'Cobrancosa' are two of most recognized Portuguese cultivars for VOO production. From the six Protected Designation of Origin (PDO) products for olive oil registered in Portugal, both 'Galega Vulgar' and 'Cobrancosa' are present in five of them, revealing their unique quality and sensory characteristics when Portuguese VOO are considered. Olive fruit ripening is a well-known variable that influences the presence and respective structural availability of specific PCs [28]. As demonstrated by [PERSON] et al. [29], PCs present an important role on the organoleptic evaluation and nutritional value of the VOO derived from these two cultivars, being the phenolic profile deeply related with the ripening stage. Therefore, harvesting date will influence the presence of different taste notes and functional value of the produced VOO. As our results show, along the ripening period, olive fruits from 'Galega Vulgar' achieved comparatively higher MI levels and OPDW accumulation content at a much earlier stage (Figure 5c,d), in agreement with a previously reported study regarding VOO derived from the same cultivars [30]. For both cultivars, a high correlation between MI and OPDW was observed (r = 0.925 and r = 0.899, respectively for 'Cobrancosa' and 'Galega Vulgar'), which confirms the MI as a good preliminary visual tool to predict appropriate harvesting time for olive oil production [31]. However, when a high quality and functional VOO is desired, other variables such as the phenolic fraction should be considered. 'Galega Vulgar' olive orchards are generally highly susceptible to diseases such as anthracose [32], which is the main phytopathological limiting factor affecting olive production in Portugal. This disease may be caused by several fungus species belonging to the genus _Colletotrichum_ and mainly affects mature olive fruits, starting to be observed during the autumn [33]. Considering the MI and OPDW reported in this study for S3 ripening stage of 'Galega Vulgar', aligned with the highest OLE and VERB registered concentrations (respectively, 26,304 \(\pm\) 10,930 and 4247 \(\pm\) 361 mg/Kg), harvesting at this considerably early stage (middle of October) could help reducing the susceptibility of anthracose occurrence for this cultivar, with no loss in the oil yield and taking advantage of a considerably high phenolic content. As observed in Table 1, the harvesting day occurred approximately one month later, which does not represent any significant increment (\(p\)-value \(>\) 0.05) in OPDW values (34.59 \(\pm\) 0.25% at S3 and 34.28 \(\pm\) 0.63% at S6). Therefore, the MI can be a pmay be viewed as a good predictor for 'Galega Vulgar' optimal harvesting time, associated with OLE and VERB higher concentrations, which might confer an additional protection towards diseases that normally affect olive orchards. To the best of our knowledge, there is no reported information related to defensive mechanisms for 'Galega Vulgar' in relation to phenolic compounds, but since OLE is associated with an endogenous defensive system against invasive species [34], such as _Bactrocera olea_[35], the high OLE values registered for this cultivar, especially at S3, should confer it a relatively good natural resilience against infestations. By itself, OLE will not confer any considerable bioactive protection to the fruit, but when exposed to the highly specific \(\beta\)-glcosidase enzymes, caused by cellular membrane rupture, its enzymatic hydrolysis will produce highly reactive aldehyde molecules [36; 37]. In conjugation with OLE, \(\beta\)-glcosidaseactivity also suffers changes along fruit ripening. As reported by [PERSON] et al. [36], the levels of \(\beta\)-glucosidase activity tend to be in accordance with OLE content in olive fruit, higher before the fruit is fully ripe, and gradually decreasing when the fruit turns mature, mainly due to the senescence of cellular tissues that will put \(\beta\)-glucosidase in contact with OLE, promoting its natural hydrolysis until their amounts turn merely residual.