ABSTRACT
Grape pomace, the main by-product from winemaking industry, accounts for 20–30% of processed grape weight and still contains valuable compounds. Valorization of pomace by extracting phenols can be a further step towards a “near zero-waste society” direction. The present work aimed at the selection of the best extraction conditions for phenol recovery from Sangiovese and Montepulciano (Vitis vinifera L.) mixed winery pomace. Different solvents were screened in 2 h incubation at 30°C and 50°C, with 1:10 and 1:5 solid/liquid ratios, with or without ultrasound pre-treatment. Total phenol yields were measured in all extracts and best extracts were characterized for flavonoid, flavanol and anthocyanin contents and for total antioxidant activity. In conclusion, 75% acetone led to the highest compound extractions, followed by 50% acetonitrile and 50% ethanol. Higher yields were obtained with 1:5 solid/liquid ratio. The ultrasound pretreatment did not significantly affect compound recovery, while better extractions were achieved with temperature increase.
