Green extraction of phenolic compounds from olive pomace: optimization of autohydrolysis conditions and evaluation of potential applications

Abstract

This study evaluated the use of autohydrolysis as a green method to extract biophenols with antioxidant and antibiofilm activities from Uruguayan olive pomace (OP), considering the formation of degradation compounds such as 5-hydroxymethylfurfural (HMF). Response surface methodology was utilized to evaluate the effect of temperature, extraction time and liquid-solid ratio on extraction yield (EY), total phenolic content (TPC), antioxidant activity (FRAP and DPPH assays), hydroxytyrosol (HTY) content and HMF content. The optimal extraction conditions (168 °C, 24 min, and liquid-solid ratio of 20 mL/g) were determined to maximize EY (25.65 g/100 g), TPC (28.60 mgGAE/g), antioxidant activity (FRAP: 328.50 µmolFSE/g; DPPH: 122.33 µmolTRE/g) and HTY content (2.79 mg/g) while minimizing HMF content (0.92 mg/g). Under these conditions, the obtained extract showed greater protection for sunflower oil than the synthetic antioxidants tested (BHA and BHT) and demonstrated the ability to inhibit biofilm formation of Candida albicans and Staphylococcus aureus.