Characterization of Unripe Grapes (Vitis vinifera L.) and Its Use to Obtain Antioxidant Phenolic Compounds by Green Extraction

Thinning pruning is a process in modern viticulture to improve product quality when grapes are still the immature fruit stage. Unripe grapes, which waste, mostly consumed locally as verjuices meet domestic demand. This study aims optimize more efficient “green” technique for extraction of total phenolic compounds (TPC) and antioxidant capacity (AC) from three varieties unripe grape juice by response surface method (RSM) using ultrasound-assisted (UAE). The influence temperature (25–65°C) time (5–30 min) on content (DPPH CUPRAC) was investigated. In this study, physicochemical properties, mineral composition, organic acid components different were also As result, optimal points (12 (30°C) determined. All independent variables found be significantly effective TPC AC during UAE. Verjuices rich source antioxidants, phenols, acids, minerals, vitamin C. expected contribute evaluation wastes, very bioactive components, increase its economic potential expanding local production, thus contributing sustainable agri-food processing.