Frost events and extreme weather phenomena greatly affect several characteristics of the
olive fruit. This study evaluated the impact of frost on the morphology, composition (moisture,
fat, fatty acids, tocopherols, and total phenolic contents), and antioxidant activity of olives of cv.
Santulhana. A total of 14 trees from the same geographical region (Santulhão, northeast of Portugal)
were chosen, including trees subjected or not subjected to frost conditions (n = 7 each). The results
showed that frost led to morphological changes in olive fruits, particularly in terms of weight and
diameter, which were imposed by a huge decrease in the moisture content (-20%). Fat relative
content increased as a consequence of the water loss (+29% in fresh pulp weight), with a slight
reduction of the relative abundance of saturated fatty acids (-4%) and tocopherol contents in the
fat (-17%). However, the total phenolic contents and antioxidant activity were severely affected
(-70% and -42%, respectively), with potential consequences for the olive oil stability and sensorial
attributes. Principal component analysis showed that both morphological and chemical parameters
could be used as biomarkers to identify olives subjected or not subjected to frost. The overall negative
impact of frost on the minor antioxidant contents of cv. Santulhana olives may anticipate a quality
loss of olive oils extracted from olives affected by frost.
The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for
financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020) and to REQUIMTELAQV
(UIDB/50006/2020) units and to the Associate Laboratories for Green Chemistry-LAQV
(UIDB/50006/2020) and SusTEC (LA/P/0007/2020). Nuno Rodrigues thanks to National funding
by FCT—Foundation for Science and Technology, P.I., through the institutional scientific employment
program-contract. Ana I. Rodrigues thanks the financial support by OleaChain project “Skills for
sustainability and innovation in the value chain of traditional olive groves in the Northern Interior of
Portugal” (NORTE-06-3559-FSE-000188).
