This paper proposes postharvest ozone fumigation (as a method) to control microorganisms and evaluate
the effect on polyphenols, anthocyanins, carotenoids and cell wall enzymes during the grape dehydration
for wine production. Pignola grapes were ozone-treated (1.5 g/h) for 18 h (A = shock treatment), then
dehydrated or ozone-treated (1.5 g/h) for 18 h and at 0.5 g/h for 4 h each day (B = long-term treatment)
during dehydration. Treatment and dehydration were performed at 10 C. No significant difference was
found for total carotenoid, total phenolic and total anthocyanin contents after 18 h of O3 treatment. A significant
decrease in phenolic and anthocyanin contents occurred during treatment B. Also carotenoids
were affected by B ozone treatment. Pectin methylesterase (PME) and polygalacturonase (PG) activities
were higher in A-treated grapes during dehydration. Finally, ozone reduced fungi and yeasts by 50%.
Shock ozone fumigation (A treatment) before dehydration can be used to reduce the microbial count during
dehydration without affecting polyphenol and carotenoid contents.