Effects of chitosan and phosphite treatments on total polyphenol content and antioxidant power of different grape berry tissues and wines
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Data di Pubblicazione:
2009
Citazione:
Effects of chitosan and phosphite treatments on total polyphenol content and antioxidant power of different grape berry tissues and wines / S. Vitalini, F. Faoro, G. Di Tommaso, D. Di Tommaso, M. Borgo, A. Piaggesi, G. Fico, F. Tomé, M. Iriti. ((Intervento presentato al convegno Resistenza indotta per il controllo di malattie delle piante : efficacia e meccanismi di azione di uno strumento sostenibile tenutosi a Ancona nel 2009.
Abstract:
Induced resistance by plant activators represents a promising perspective
in crop protection (Gozzo, 2004). As elicitors, these products are able to boost the plant own defences against a broad spectrum of pathogens, a phenomenon known as
systemic acquired resistance (SAR). Among plant activators, benzothiadiazole (BTH)
and chitosan proved to be effective in controlling grapevine fungal disease (Iriti et al., 2004; Dagostin et al., 2006; Trotel-Aziz et al., 2006), meanwhile improving the
content of grape antioxidant compounds, i.e. anthocyanis, proanthocyanidins, stilbenes
and melatonin (Iriti et al., 2004, 2005, 2006, 2008). In this work, we assayed the total polyphenol (TP) content and antioxidant power of two different grapevine (Vitis vinifera L.) cultivars, Montepulciano d’Abruzzo and Merlot, treated with kendal-COPS® (kC® Valagro, a formulation based on chitosan and Cu and Mn as microelements) and with phosphite (potassium phosphonate), respectively. Furthermore, we determined the TP content and antioxidant power of the experimental wines produced by microvinification of Montepulciano d’Abruzzo treated and untreated grapes.
Our results showed that the TP content, measured by Folin-Ciocalteau colorimetric assay, was higher in all kC®- and phosphite-treated grape berry tissues of both cultivars, compared with either untreated controls or conventional fungicide treated
plants. A similar trend was observed with regard to the antioxidant power of the grapes, assessed by DPPH (2,2-diphenyl-1-pycryl hydrazyl) free radical scavenging test. However, the results obtained from the analysis of Montepulciano d’Abruzzo wine revealed a different pattern, with a higher TP content and antioxidant power in the sample produced from control grapes in respect to those obtained from both kC®- and fungicide-treated grapes. This discrepancy could be due to the skin tissue thickening induced by kC®, a typical plant defence response, which could reduce the polyphenol extraction during microvinification, but would hardly occur in a conventional winemaking process.
Though this aspect needs further investigation, it can be concluded that open
field treatments with plant resistance activators deserve particular attention, not only as a low-environmental impact strategy in the management of grapevine fungal
diseases, but also because they contribute to improve the bioactive phytochemicals
content of grape.
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Keywords:
fungal diseases ; grapevine phytoalexins ; induced resistance ; phytochemicals
Elenco autori:
S. Vitalini, F. Faoro, G. Di Tommaso, D. Di Tommaso, M. Borgo, A. Piaggesi, G. Fico, F. Tomé, M. Iriti
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