The expansion of fruit processing industries results in a significant amount of by-products, including peels, seeds, skins, pomace, and rinds, which are rich in bioactive compounds like polyphenols, flavonoids, carotenoids, and dietary fiber. These processing by-products are often deemed of minimal value relative to the processed fruit, largely due to the absence of efficient extraction methods. In this study, ultrasound-microwave assisted extraction (UMAE) technology was used to extract bioactive components from pomegranate (Punica granatum L.) peel using ethanol as a solvent. The influence of the combined power (ultrasonic 200 W + microwave 100–300 W), extraction time (10–30 min.), liquid to solid ratio (LSR) (20:1–60:1 mL/g) and solvent concentration (30–70 vol%) on extraction yield, total phenolic content (TPC), total flavonoids content (TFC) and 1,1-diphenyl-2-picrylhydrazyl- radical scavenging activity (DPPH-RSA) was investigated. The optimal conditions using response surface methodology (RSM) for UMAE were found to be an ultrasonic power of 150 W, LSR of 50:1 mL/g, a solvent concentration of 60 %, and an extraction time of 15 min. Under the optimized conditions, 64.964 % of extraction yield, 152.089 mg GAE/g DW of TPC, 38.566 mg QE/g DW and 88.892 % of DPPH-RSA were obtained. The concentration–time data were examined using a second-order rate kinetic model to calculate the extraction constant and activation energy. The thermodynamic analysis indicated that the UMAE process is both spontaneous and endothermic. Scanning electron microscopy (SEM) images, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectra of resulted extract under optimal conditions revealed a disrupted structural network, analyzed the nature and identified the primary functional groups, respectively. This research showed that using UMAE with ethanol is a quick, effective, and eco-friendly method for extracting pomegranate peel.
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