## 3 Results and Discussion
### Statistical Analysis of the VOCs Profile in the Sabrina and Elide Strawberry Samples
#### 3.2.2 Linear Mixed-Effect Modelling (LME) on Sabrina Data Set  
The LME analysis conducted on the VOCs profiles of Sabrina discovered 50 VOCs differently expressed comparing PE and N5 mulching, 56 between PE and N18, and 59 matching N5 and N18. Among 50 VOCs differently expressed between PE and N5 mulching, only 7 volatiles (E20, E24, E34, A15, T2, T3, and F1) showed a statistically significant up-regulation in the strawberries produced on N5 mulch, while 43 VOCs (E1-E3, E6, E9, E11-E15, E18, E19, E21-E23, E25, E27, E29, E31, E33, E35, Ald1, Ald3, Ald4, Al4, Al4, Ac1-Ac4, Ac6-Ac11, T4, T5, T7, T8, F3, and L1-L3) were down-regulated compared to the PE film. The amount of the remaining 15 compounds showed a non-statistical difference between the two treatments (PE vs. N5) (Figure 2; Table S2). A substantially different picture emerged from the PE vs. N18 comparison since out of 56 VOCs differently expressed between the two films, 47 components (E1-E3, E5-E14, E16, E18, E19, E22, E24-E29, E31, E33, E34, Ald1, Ald2, Ald4, Ald5, All1-Alt, Ac3, Ac4, Ac7, Ac8, T2-T5, T7, T8, F1, L1, and O1) were up-regulated in the fruit grown on N18 mulch, while only 9 VOCs (E15, E17, E20, Ald3, Ac1, Ac10, Ac11, F3, and L3) were down-regulated (Figure 2; Table S2). The content of the remaining nine VOCs was not statistically different between the two treatments (PE vs. N18) (Figure 1; Table S2). In Sabrina cv, 54 (E1-E3, E5-E14, E16, E18, E19, E22-E29, E31, E33-E35, Ald1, Ald2, Ald4, Ald5, Al1-Alt, Ac2-Ac4, Ac6-Ac9, Ac11, T2-T5, T7, T8, F3, L1, L2, and O1) out of 59 VOCs differently expressed between N5 and N18 were up-regulated in berries grown using N18 mulching film. On the contrary, five (E15, E17, E20, Al5, and F1) were more abundant in fruit produced using N5 film, while the amount of the remaining six VOCs was comparable between the treatments (N5 and N18) (Figure 2; Table S2). In relation to the comparison of PE vs. N5 for Sabrina cv, among the seven volatiles (E20, E24, E34, A15, T2, T3, and F1) up-regulated in N5 strawberries, hexyl butyrate (E24), _cis_-linalool oxide (T2), and mesifuran (F1) are sweetness-enhancing volatiles, while _trans_-2-hexen-1-ol-acetate (E20) has shown a strong negative association to liking [10; 17; 18]. Moreover, octanol (Al5) has been previously reported in fruit at late stages of maturation, and mesifuran (F1) is known to increase during the fruit ripening, imparting a carmed or cotton-candy-like flavour in red strawberries [14; 24]. Among the 43 volatiles (E1-E3, E6, E9, E11-E15, E18, E19, E21-E23, E25, E27, E29, E31, E33, E35, Ald1, Ald3, Ald4, Al4, Ac1-Ac4, Ac6-Ac11, T4, T5, T7, T8, F3, and L1-L3) that dominate the VOCs profile of Sabrina PE fruit, methyl butyrate (E3), ethyl butyrate (E6), butyl acetate (E9), ethyl pentanoate (E11), pently acetate (E13), methyl hexanoate (E14), ethyl hexanoate (E15), _cis_-3-hexen-1-ol-acetate (E19), ethyl octanoate (E25), hexyl hexanoate (E31), nonanal (Ald3), benzaldehyde (Ald4), 2-methylbutanoic acid (Ac4), decanoic acid (Ac9), linalool (T4), \(\gamma\)-decalactone (L2), and \(\gamma\)-dodecalactone (L3) positively affect liking and/or sweetness [10; 17; 18]. Several of these VOCs, including E3, E6, E11, E14, E15, Ald1, T4, L2, and L3, are increased in ripe fruit, imparting the characteristic fruity notes of mature strawberries [10; 23]. Consistent with these findings, the strawberries cv. Sabrina grown on PE could be preferred by the consumers compared to the N5 fruit because of an increased number of volatiles, with a positive impact on the consumers' liking. Moreover, since in the N5 samples, a larger number of volatiles associated with ripe strawberries were detected, it can be hypothesized that the N5 film promotes an early ripening of the fruit with respect to PE.