# Impact of Frost on the Morphology and Chemical Composition of _cv_. [PERSON]
## 3 Results and Discussion  
### Morphological Characterization  
Olive fruits can be damaged by frost, i.e., when the air temperature decreases to 0 \({}^{\circ}\)C or lower, promoting freezing of the fruits' pulp water, reducing enzymatic and biochemical reactions, as well inhibiting microbial activity [24; 25]. Thus, olive fruits and endocarps subjected or not subjected to natural freezing-defrosting cycles before harvest were morphologically characterized according to the UPOV parameters [18], and the data are listed in Table 1. The values obtained for size (length and diameter) and weight for the olives not affected by frost are in accordance with previous data for this cultivar [17], strengthening _cv._ Santulhana size attributes in comparison with other typical cultivars from the Tras-os-Montes region, such as _cvs._ Cobrancosa, Verdeal Transmontana, and Madural. Frost promoted a significant reduction in the diameter and weight of the studied olives (minus 6 and 13%, _p_-value < 0.05) but not their length. This decrease could be related to the significant loss of moisture observed in olive fruits affected by frost (minus 20%, _p_-value < 0.05), associated with a reduction of the \"firmness\" of olive fruits (not evaluated). In fact, water crystallization inside the fruit pulp cellular structures is followed by defrosting cycles, creating cellular damage that facilitates water loss, which leads to water evaporation and loss of weight and, consequently, a weight and diameter reduction. Since the endocarp is not affected by water crystallization as the pulp, the pulp-to-stone weight ratio significantly decreased for olives subjected to frost (minus 20%, _p_-value < 0.05). These results are in accordance with previous studies, which reported that the weight of olives grown at lower temperatures (higher altitudes) was lower than the weight of fruits grown at higher temperatures [26; 27]. In opposition, the total fat content of olives affected by frost was significantly greater compared to the weight of unfrosted olives (plus 29%, _p_-value < 0.05). This can be explained by the loss of water, as stated above, which is also indicative that the potential cellular damage imposed by water crystals does not affect the oil content. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **No Frost** & **With Frost** & _p_**-Value** \\ \hline Olive Fruit & & & \\ \hline Length (mm) & 24.8 \(\pm\) 1.0 & 24.3 \(\pm\) 0.9 & 0.333 \\  & (23.4 \(\pm\) 1.6 to 25.9 \(\pm\) 1.6) & (23.1 \(\pm\) 0.7 to 25.4 \(\pm\) 1.4) & 0.014 \\ Diameter (mm) & 17.8 \(\pm\) 0.6 & 16.7 \(\pm\) 0.8 & \\  & (16.7 \(\pm\) 1.1 to 18.5 \(\pm\) 0.8) & (15.2 \(\pm\) 0.7 to 17.5 \(\pm\) 0.8) & \\  & 4.5 \(\pm\) 0.4 & 3.9 \(\pm\) 0.5 & \\ Weight (g) & (4.0 \(\pm\) 0.7 to 5.1 \(\pm\) 0.7) & (3.1 \(\pm\) 0.3 to 4.4 \(\pm\) 0.5) & \\ \hline Stone & & & \\ \hline Length (mm) & 18.0 \(\pm\) 0.8 & 18.3 \(\pm\) 0.5 & \\  & (16.4 \(\pm\) 1.2 to 18.5 \(\pm\) 0.6) & (17.3 \(\pm\) 1.0 to 18.8 \(\pm\) 1.1) & \\ \hline Diameter (mm) & 9.2 \(\pm\) 0.3 & 9.1 \(\pm\) 0.3 & \\  & (8.7 \(\pm\) 0.5 to 9.6 \(\pm\) 0.5) & (8.6 \(\pm\) 0.5 to 9.6 \(\pm\) 0.4) & \\ \hline Weight (g) & 0.9 \(\pm\) 0.1 & 0.9 \(\pm\) 0.1 & \\  & (0.7 \(\pm\) 0.1 to 1.0 \(\pm\) 0.1) & (0.8 \(\pm\) 0.1 to 1.0 \(\pm\) 0.1) & \\ \hline Weight ratio Pulp/Stone & 4.4 \(\pm\) 0.3 & 3.5 \(\pm\) 0.4 & 0.001 \\ \hline Moisture (\%) & 59.1 \(\pm\) 6.2 & 47.5 \(\pm\) 3.3 & 0.001 \\ Fat (\%) & 25.9 \(\pm\) 3.6 & 33.4 \(\pm\) 3.8 & 0.001 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Morphological characteristics of olive fruit and stone, moisture, and fat contents of _cv._ Santulhana of olive fruits affected or not affected by frost (mean \(\pm\) standard deviation; minimum and maximum values in brackets). The feasibility of using the moisture and fat contents as differentiating parameters to recognize/distinguish _cv._ Santulhana olives subjected or not subjected to frost were further evaluated using a PCA.