Abstract
1. Introduction
Disease resistant hybrid grape cultivars (DRHGCs) are increasingly topical, particularly since EU legislation changed to allow their use in DOC wines [1]. DRHGCs allow for the production of healthy, high quality grapes with minimal pesticide usage, and thus effecting positive social and environmental transitions [2]. However, the chemistry of DRHGCs is unique, and this can create challenges for the production of high quality wines (PIWI wines) [1,3].
2. Methods
Wines produced from both DRHGCs and conventional Vitis vinifera cultivars were compared using LC-MS, colorimetry (CIELab color space), oenological multiparametric analysis and sensory characterization. The preliminary results presented here are from wines used for a ‘round table’ sensory session (used to generate sensory attributes for training and wine description).
3. Preliminary results
As expected, the anthocyanin content of the red wines were particularly distinctive [4]. DRHGC wines (PIWI wines) contained diglucoside and triglucoside anthocyanins, which were not present in Vitis vinifera wines. In addition, anthocyanin rhamnoside derivatives were present. Work on quantification has yet to be undertaken, but the patterns of anthocyanins differs between DRHGCs and V. vinifera (Figure 2). Structures of the anthocyanins and fragmentation patterns were hypothesised based on a comparison of retention times and MS/MS with red cabbage extract [5] (Figure 1); other LC-MS peaks that presented the same mass/charge ratio but much higher RT have been observed, and their identification is in progress. These differences were also reflected in the wine colour, with the DRHGCs being darker, more yellow, and more magenta than the V. vinifera wines.
Differences in the polyphenol of red wines were also noted, with a PCA providing good separation between DRHGC and V. vinifera wines. The separation was not as obvious for white wines. In contrast, preliminary results suggest that the peculiar proanthocyanidin (PAC) patterns observed may be more valuable for white wines than for red wines.
Preliminary sensory analysis of white wines has begun, and reinforces the distinctiveness of DRHGCs shown by LC-MS analysis. Interestingly, sensory analysis has so far shown no preference towards V. vinifera wines, in contrast to other studies [6,7].
Fig. 1. MS/MS fragmentation of red cabbage cyanidin triglucoside
Fig.2. PCA of round table red wines anthocyanins, showing clear separation between DRHGC wines (Rubus and Robustus, both blends of ‘Monarch’ and ‘Cabernet Cortis’) and Vitis vinifera blends (‘Lagrein’ and ‘Cabernet Sauvignon’) on PC1.
4. Preliminary conclusions and future work
From the preliminary analysis already conducted, it can be seen that PIWI wines are distinctive in terms of their chemical profiles. While our results are still preliminary, they show the distinctive character of PIWI wines from South Tyrol. These results were also reflected by the sensory analysis. Interestingly, no differences in consumer preference between DRHGC and V. vinifera wines were noted.
Wineries may efficiently adapt the winemaking practices required for processing PIWI grapes. In addition, educated consumers may be well receptive to the flavours and aromas of PIWI wines, thus supporting the efforts of the EU policy towards the ecological transition.
References
1. G. Duley, A.T. Ceci, E. Longo, E. Boselli; Comprehensive Reviews in Food Science and Food Safety (2023).
2. K. Pedneault, C. Provost; Scientia Horticulturae 208 (2016) pp. 57–77.
3. P-L Teissedre; OENO One 52 (2018) pp. 211–217.
4. M. De Rosso, L. Tonidandel, R. Larcher, et al.; Analytica Chimica Acta 732, 120–129 (2012).
5. Wiczkowski, W, Szawara-Nowak, D & Topolska, J. Red cabbage anthocyanins: Profile, isolation, identification, and antioxidant activity. Food Research International 51, 303–309 (2013).
6. A. Fuentes Espinoza, A. Hubert, Y. Raineau, C. Franc & É. Giraud-Héraud; OENO One 52 (2018).
7. L. Nesselhauf, R. Fleuchaus, L. Theuvsen; International Journal of Wine Business Research 32 (2019) pp. 96–121