Green approach for phenolic recovery: Auricularia fuscosuccinea enzymes applied to citrus processing waste

Abstract

Citrus processing waste represents a potential source of bioactive molecules, particularly phenolic compounds with antioxidant activity. Enzyme-assisted extraction using an enzymatic cocktail from Auricularia fuscosuccinea was evaluated for the recovery of phenolic compounds from orange, grapefruit, and citric blend processing waste. First, the effect of operative factors on β-glucosidase activity was evaluated. Then, the effect of waste type and extraction method on total phenolic content, antioxidant activity, and phenolic profiles by HPLC was determined. Finally, the in vitro cytotoxicity was evaluated. The optimal factors for β-glucosidase activity were 60 ◦C, pH 4.8, and 11 h, which are suitable conditions for enzyme-assisted extraction. The enzyme-assisted extraction of citrus blend waste resulted in the highest phenolic compounds content and antioxidant activity (511.20 ± 19.51 mg gallic acid equivalents 100 mL− 1 of total phenolic content, and 27.90 ± 1.13 mg gallic acid equivalents 100 mL− 1, and 1691.02 ± 0.05 mg gallic acid equivalents 100 mL− 1 for DPPH and ABTS assays, respectively). Enzyme-assisted extraction promoted the release of 4-OH-benzoic acid for the three wastes. Moreover, the content of p-coumaric and vanillic acids increased on the citrus blend matrix. Additionally, naringin and hesperidin were detected at higher concentrations than phenolic acids across all extraction methods. Citrus blend extracts presented an IC50 of 44.61 mg gallic acid equivalents 100 mL− 1 in the cytotoxicity assay, promoting cell viability at lower doses. These findings highlight the potential of fungal enzyme-assisted extraction as an efficient, safe, and low-cost strategy for recovering phenolic compounds from citrus processing waste.