Extraction Methodology and Power Ultrasound Effects on Phenolic Compounds and Antioxidant Activities of Two Tunisian Grape Varieties

Two cultivated grape varieties in Tunisia were investigated for their phenolic and antioxidant activities contents in the aim to inspect maceration and ultrasound-assisted system influences as extraction methodologies.The effect of the increasing ultrasonic power on these components were also assessed.In fact, the superiority of the ultrasound-assisted technique to extract phenolic compounds and improve antioxidant activities, was clearly as compared to conventional extraction.Besides, dried plants showed a better phenolic conservation and an important antioxidant power as compared to fresh plants.Regardless of the extraction technique used and the state of the fruit, red grape showed a better phenolic quantities and the utmost antioxidant capacities in comparison to green one.On the other hand, the increasing ultrasound power applied seems to have less influence on antioxidant parameters.The chromatogram analysis reveals the presence of phenolic acids and flavonoids.These findings highlights the superiority of non-conventional extraction system.