Optimization of Enzymatic Assisted Extraction of Bioactive Compounds from Olea europaea Leaves

Nowadays, the circular economy trend drives researchers in the recovery of various bioactive compounds from agri-food by-products. Enzyme-assisted extraction (EAE) has been shown to be an innovative green technology for the effective extraction of various phytochemicals from agri-food section by-products; therefore, this study aimed to evaluate the application of EAE as green technology to obtain extracts from olive leaves (Olea europaea) for potential industrial production. The used enzymes were Celluclast, Pectinex XXL and Viscozyme L. EAE was conducted under various enzyme dose combinations and an incubation time of 120 min. Obtained extracts were characterized in terms of total polyphenols (TP) and total antioxidant activity (AA). Firstly, the enzyme synergistic effect in the enzymatic extraction of polyphenols was evaluated. TP optimal extraction conditions (468.19 mg GAE (gallic acid equivalent)/L of extract) were achieved after EAE using Pectinex and Viscozyme enzymes (50–50 v/v) and for AA (69.85 AA%). According to the above results, a second experiment investigated the effect of incubation time (min.) and enzyme dose (mL) on the optimal extraction conditions of olive leaves. The final results after optimization were 75% higher than the control sample for the TP content (605.55 mg GAE/L) and 8% higher for the AA (70.14 AA%). These results indicated that EAE is an excellent choice for the green extraction of polyphenols from the olive leaves.