Characterization of ‘Cabernet Sauvignon’ pomace extracts and evaluation of antifungal potential of Alternaria sp. and Fusarium sp.

This study was conducted to capitalize on the waste produced by the vinification process which proved to be important sources of bioactive compounds with significant antifungal properties. ‘Cabernet Sauvignon’ grape pomace extracts were characterized in terms of total polyphenol content, antioxidant potential, but also evaluated in terms of antifungal effect against phytopathogenic fungi (Fusarium sp. and Alternaria sp.). The isolates used in this study were grown on three potato-dextrose-agar culture media, Czapek Dox and Malt-Agar. The highest amount of polyphenols was determined from the extract obtained by the microwave-assisted method (42.76 mg/g GAE), followed by the extract obtained by maceration (30.37 mg/g GAE). The lowest amount was obtained by the ultrasound-assisted method (15.06 mg/g GAE). However, the highest antioxidant activity was determined in the macerated extract, TEAC = 0.0523. The results of in vitro tests clearly indicated a high inhibitory percentage on the mycelium growth rate and, respectively, a significant decrease in spore germination power in Fusarium sp. (91.56%). However, for the pathogen Alternaria sp. further studies are needed to correctly validate the percentage of inhibition, as alcohol has been shown to have a negative effect on it.