Selective ultrasound‐assisted aqueous extraction of polyphenols from pomegranate peels and seeds

In this study, the optimization of ultrasound‐assisted aqueous extraction of polyphenols from pomegranate peels and seeds was conducted. A 10‐min sonication (tu ) pre‐treatment (≈60 W) accelerated the extraction kinetics and intensified the polyphenol recovery from peels and seeds. Ultrasound pre‐treatment permitted the selective recovery of polyphenols from peels by maintaining a constant concentration of the total soluble matter (°Brix) before and after sonication. Two different near‐linear correlations were found between soluble matter and polyphenol extraction for the peels’ and the seeds’ extracts. Luminescence emission spectra showed significant differences between peels and seeds extracts (tu = 10 min then diffusion for 200 min) below 450 nm and above 600 nm. Ultrasound pre‐treatment enhanced the quantity of the extracted molecules from peels and seeds without affecting their diversity. The optimal ultrasound pre‐treatment duration was 10 min, since it ameliorated the polyphenol extraction compared to 5 min, and gave the same yield as 20 min.