Fruit and vegetable processing wastes as natural sources of antioxidant-rich extracts: Evaluation of advanced extraction technologies by surface response methodology

This study is focused on the recovery of polyphenols from vegetable and fruit residues further evaluation antioxidant features extracts. Spinach orange have been selected as representative matrices for a more comprehensive since they contain significant amount that could be used in food, pharmaceutical and/or cosmetic industries. Extraction spinach waste was performed using three extraction techniques: ultrasound-assisted (UAE), microwave-assisted (MAE), pressurized liquid (PLE). Tested factors include percentage organic solvent (ethanol 0–80%), acidity (0–0.5% HCl), time (0–30 min) temperature (25–120 °C). Optimal conditions stablished by design experiments (DoE). The performance process has preliminarily assessed overall polyphenolic content given high-performance chromatography (HPLC) Folin–Ciocalteu index. In addition, reducing power antiradical capacity extracts also determined. For spinach, best corresponded to UAE with mixture ethanol/water/HCl ratio 80/19.9/0.1 (v/v/v) at 25 °C an 30 min, providing 0.82 mg gallic acid equivalent (GAE) per g fresh weight (fw). matrix, PLE chosen 60/39.9/0.1 80 15 3 GAE g−1 fw. However, proposed industrial scale, due its simplicity low cost, among other reasons.