## 3 Results and Discussion
### Statistical Analysis of the VOCs Profile in the Sabrina and Elide Strawberry Samples
#### 3.2.1 Linear Mixed-Effect Modelling (LME) on Elide Data Set
Finally, hexanal (Ald1) and T4 are associated with the fruit maturation, as the enzymes involved in their biosynthetic pathway exhibited the highest activity at the full-red stage [19, 20, 21]. The findings reported above suggest that the samples obtained using the N5 film can meet the consumers' expectations of sweetness more that the PE samples, as N5 fruit is characterized by a larger number of the so-called sweetness-and/or aroma-enhancing volatiles [10,17]. In fact, among all the sensory attributes, sweetness is considered the principal driver for consumers, who particularly prefer sweet and aromatic (\"intense fruity\") strawberries [10,17]. Moreover, based on the higher number of ripening-associated VOCs found in the N5 samples, it can be hypothesized that the N5 film favours an early ripening of strawberries. Within the Elide cv, 38 VOCs (E1, E3, E7, E9, E11, E12, E14, E15, E18, E21, E22, E24-E26, E31-E33, Ald1-Ald4, Al1, Al3-A15, Ac1, Ac2, Ac4, Ac8, T1, T2, T4-T7, F1, F2, and O1) were up-regulated in the fruits cultivated using N18 in comparison to PE, while 14 compounds (E16, E17, E19, E20, E34, Ald6, Ac5, Ac6, Ac9, T8, F3, and L1-L3) showed down-regulated levels in berries grown using PE film. The amount of the remaining 17 volatiles was comparable between the treatments (PE and N18) (Figure 1; Table S1). Among the 38 volatiles up-regulated in Elide N18 fruits, eight esters, including methyl butyrate (E3), butyl acetate (E9), ethyl pentanoate (E11), _trans_-ethyl 2-butyrate (E12), methyl hexanoate (E14), ethyl hexanoate (E15), hexyl butyrate (E24), and ethyl octanoate (E25); six terpen,most of all _cis_-linaloid oxide (T2) and linalool (T4); two aldehydes, nonanal (Ald3) and benzaldehyde (Ald4); two lactones, \(\gamma\)-decalactone (L2) and \(\gamma\)-dodecalactone (L3); and mesinfuran (F1) and 2-methylbutanoic acid (Ac4) are generally believed as positively correlated with \"acceptance\" regardless of the sugar content, while two compounds, ethyl 2-methylbutyrate (E7) and 2-hexenal (Ald2), have been reported to have a negative correlation related to liking [10; 17; 18]. Many of the above-described volatiles, including ethyl pentanoate (E11), methyl hexanoate (E14), ethyl hexanoate (E15), _trans_-2-hexenyl butyrate (E26), hexanal (Ald1), 2-hexenal (Ald2), hexanoic acid (Ac4), mesifuran (F1), and furaneol (F2), also indicated as key odorants in strawberry flavour, increase during the fruit ripening, as the enzymes involved in their biosynthetic pathway exhibit the highest activity at the full-red stage [18; 19; 20; 21]. Among the 14 (E16, E17, E19, E20, E34, Ald6, Ac5, Ac6, Ac9, T8, F3, and L1-L3) VOCs statistically more abundant in the PE Elide strawberries, compared to N18, hexyl acetate (E17), _cis_-3-hexen-1-ol acetate (E19), decanoic acid (Ac9), L2, and L3 have been directly associated with the \"sweet\" taste sensation, while isoamyl butyrate (E16) and _trans_-2-hexen-1-ol-acetate (E20) are negatively associated with both sweetness and consumers' liking [10; 17]. Overall, the results obtained by the comparison of PE and N18 in Elide cv. suggest that fruit grown using the N18 film can be preferred by consumers, as it is described by a higher number of VOCs, showing an enhancing effect on sweetness and/or associated with the fruit ripening. In fact, notwithstanding that both \(\gamma\)-decalactone and \(\gamma\)-dodecalactone have been detected only in PE strawberries (Table S1), no direct correlation between aroma sensation and the lactone content have been observed, suggesting that the other VOCs can significantly contribute to the sensory perception [22]. Out of the 58 differently expressed VOCs between N5 and N18 in Elide cv, 43 compounds (E1-E4, E7-E9, E11-E15, E18, E22, E24-E29, E31, E33, Ald1-Ald5, A1, Al14, Al5, Ac1, Ac2, Ac4, Ac8, T1, T2, T4-T7, F1, F2, and O1) showed a higher level in berries grown using N18 mulching film (Table S1).