Innovative process of polyphenol recovery from pomegranate peels by combining green deep eutectic solvents and a new infrared technology

In this study, polyphenols were extracted from pomegranate peels with solid-liquid (SL), ultrasound (US) and Ired-Irrad (R), a newly-patented infrared (IR) extraction technique. Deep eutectic solvents were used as green alternatives to conventional aqueous or organic solvents. The extraction process was conducted at 50 degrees C for 90 min. The biological (antiradical, antioxidant, antimicrobial and antifungal) activities of the polyphenols extracted in different solvents with the above-mentioned extraction methods were compared. The highest concentration of polyphenols (152 mg/g DM) was obtained with IR in the deep eutectic solvent. The extraction in the deep eutectic solvents using the IR technique gave the highest antioxidant and antiradical activities. Polyphenols extracts allowed the inhibition of gram-positive and gram-negative bacteria up to 87% and 95% respectively. They also inhibited the growth of the fungus Aspergillus flavus by 46%. High performance liquid chromatography (HPLC) permitted the identification and quantification of the extracted polyphenols. The solvent and the method of extraction had a high selectivity on the extraction of polyphenols.