In these studies, polyphenol values have been obtained which are more than double those in oils made from a single variety, namely Picual. This is thanks to the native Nevadillo Negro variety and the soil and climate conditions.
The results obtained demonstrate the influence of the Nevadillo Negro variety on the composition of polyphenols in D.O. Montoro-Adamuz oils, a reason why they are even more stable to oxidation the olive oils made from the single Picual variety, traditionally considered the most stable along with oils from the cornicabra variety.
Likewise, the soil and climate conditions of the mountain olive grove in the geographical area of the DO Montoro-Adamuz create a situation of stress for the olive tree, which results in an increase in the phenolic content. The acidic and shallow soils, unique to Andalusia, accentuated by the conditions of water stress on the district’s olive groves, combine with the early harvesting practices to influence the high content of polyphenols in the oils.
All of this means that DO Montoro-Adamuz oils have the highest content of polyphenols compared to other oils produced in other areas, mainly from the Picual variety, which they differ from. This fact helps ensure the great chemical stability of Montoro-Adamuz oils, a feature which has been historically recognised in the extra virgin olive oils from this district.