## 4 Conclusions  
Fifteen carotenoids, including (all\(E\))-lutein and \(\beta\)-carotene together with their 9Z isomers and 5,6-/5,8-epoxyxanthophylls, were tentatively identified by matching UV-Vis characteristics, MS spectra, and elution order, and were accurately quantified by the used analytical method. As expected, a decrease of carotenoids during ripening was observed in both the two cultivars, but this was even more noticeable in grapes treated with YE. \(\beta\)-carotene and (all\(E\))-lutein were present as the main compounds in all the analyzed samples, and the level of xanthophyll appeared to be more drastically reduced than the caroten level, especially in mature Negro Amaro and Primitivo treated grapes. Similarly, the elicitor treatment caused a more consistent decrease of violaxanthin, (9'Z)-neoxanthin, and 5,6-epoxylutein.  
Thereby, because carotenoids serve as precursors of C\({}_{13}\)-norisoprenoids, the YE treatment proved to be determinant in enhancing the aroma potential (\(\Delta C\)) of both varieties up to four-fold compared to untreated grapes. Besides this, Negro Amaro and Primitivo were principally characterized by lutein, \(\beta\)-carotene, and violaxanthin derivatives, and (9'Z)-neoxanthin derivatives, respectively. However, further research is ongoing to confirm the real characteristics of these grapes in obtaining wines which are richer in sensorial impact C\({}_{13}\) aroma compounds, such as \(\beta\)-ionone and \(\beta\)-damascenone.  
Figure 7: Principal component diagram of carotenoid derivatives in the two grape varieties (N: Negro Amaro; P: Primitivo) as affected by the treatment (C: control; YE: yeast extract). 1, violaxanthin derivative; 2, (9’Z)-neoxanthin derivative; 3, (8’S)-neochrome derivative; 4, 5,6-epoxylutein derivative; 5, luteoxanthin derivative; 6, lutein like structure derivative; 7, Z-lutein like structure derivative; 8, (allE)-lutein derivative; 9, (9Z)-lutein derivative; 10, \(\beta\)-carotene derivative.  
**Supplementary Materials:** The following are available online at [[http://www.mdpi.com/2076-3417/10/10/3369/s1](http://www.mdpi.com/2076-3417/10/10/3369/s1)]([http://www.mdpi.com/2076-3417/10/10/3369/s1](http://www.mdpi.com/2076-3417/10/10/3369/s1)), Figure S1: Extraction yields of (**a**) Negro Amaro and (**b**) Primitivo samples, Table S1: Validation parameters, linearity, repeatability (**r**), LOD and LOQ for HPLC-DAD analyses.  
**Author Contributions:** Conceptualization, P.C.; methodology, G.M., A.R.C. and L.T.; validation, P.C. and M.S.; formal analysis, M.S.; data curation, P.C.; writing--original draft preparation, P.C.; writing--review and editing, F.V. and F.A.T.-B.; visualization, F.B. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Acknowledgments:** We would like to thank LALLEMAND Italia S.p.A. for supplying the Lalvigne(r) MATURE formulation used in this work.  
**Conflicts of Interest:** The authors declare no conflict of interest. LALLEMAND had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.