In recent years, occurrences of heat waves and drought have become increasingly frequent,
highlighting the undeniable impact of climate change. The rise in temperatures and decline in
rainfall have had severe repercussions on olive trees’ behavior and olive oil production. This study
aims to evaluate the effects of two-year climate variations on olive oils from centenarian olive trees
situated in the Côa Valley region of Northern Portugal. A selection of 25 centenarian plants was
made, and the climate influence on fatty acid content, tocopherols, individual phenols, oxidative
stability, and antioxidant activity was assessed over two consecutive years. During the second year
of the study, a significant variation (p-value < 0.05) in the proportion of palmitic acid was observed,
which increased from 12.9% to 13.6%. Conversely, stearic and arachidic acids exhibited a decrease
from 2.7% to 2.3% and from 0.37% to 0.35%, respectively. Analysis of the oils revealed a noteworthy
difference (p-value < 0.05) in the concentration of -tocopherol. The concentration of oils derived
from hydroxytyrosol and tyrosol significantly decreases (p-value < 0.005) during the second year.
Additionally, significant differences (p-value < 0.005) were observed in the total phenol content and
the percentage of ABTS inhibition, both of which decreased in the second year. These findings
reinforce the notion that climatic conditions play a key role in shaping the composition of olive oils.
This research was funded by Foundation for Science and Technology (FCT, Portugal) financial
support from national funds FCT/MCTES to CIMO (UIDB/00690/2020 and UIDP/00690/2020),
SusTEC (LA/P/0007/2020) and to LAQV/Requimte (UIDB/50006/2020 and UIDP/50006/2020); to
the Project “OLIVECOA—Centennial Olive Trees in the Côa Valley Region: rediscovering the past
to enhance the future” (ref.COA/BRB/0035/2019). Nuno Rodrigues and Rebeca Cruz thanks the
FCT- Foundation for Science and Technology, P.I., for the National funding through the institutional
program contract for scientific employment.
