*3.5. Statistical Analysis*

Data were processed by means of two-way ANOVA, using Statgraphics and considering the selenium concentration and time of its administration as variables. The results were then analyzed with the least significant difference (LSD) test (*p* < 0.05). Statistically significant values were indicated with different letters. VOCs were analyzed by partial least squares discriminant analysis (PLSDA) using JMP®, v. 16 (SAS Institute Inc., Cary, NC, USA).

#### **4. Conclusions**

Although less effective than supplementation via nutrient solution, selenium treatments performed by spraying tomato plants with 1 and 1.5 mg L−<sup>1</sup> sodium selenate are effective in enriching tomatoes with Se concentrations, with no risks of toxicity for the human diet. In addition to the Se dosage, the developmental stage of the plant also seems to affect the biofortification effectiveness of the treatment with limited effects on fruit composition. Our approach to studying the physiological effect of Se-biofortification of fleshy fruit supports the evidence that the uptake of selenium causes metabolic changes in ripening fruit. This, then, results in increases in specific VOCs putatively associated with higher consumer preference scores. These changes in the aroma profile induced by Se represent a new and interesting aspect to study in future research, considering that the poor aroma of the commercial tomato varieties is one of the major causes of consumer complaints.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/10 .3390/plants10061050/s1, Table S1: List of VOCs identified in control and Se-enriched fruit samples.

**Author Contributions:** Conceptualization, A.M., F.M. and B.P.; Methodology, A.M., F.M., I.R. and B.P.; Software, A.M., A.S. and F.M.; Validation, A.M., B.P. and F.M.; Formal Analysis, A.M., I.R. and A.S; Writing—Original Draft Preparation, A.M., B.P., F.M. and A.S.; Writing—Review and Editing, B.P. and A.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on request from thecorresponding author.

**Acknowledgments:** The authors wish to thank Stefano Brizzolara, Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa (Italy), for his technical assistance in performing the VOC analyses. A special thanks to Pietro Tonutti, Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa (Italy), for reading the text and adding support through valuable comments and suggestions.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

