Abstract

Pomegranate (Punica granatum L.) peel, typically considered a processing byproduct, is a rich source of bioactive compounds such as phenolics and flavonoids, which offer antioxidant and antimicrobial benefits. This study focused on optimizing and comparing two drying methods-sun drying and tray drying along with two extraction techniques-conventional solvent extraction and ultrasound- assisted extraction (UAE) to determine the most effective approach for maximizing these beneficial properties in pomegranate peel powder. Four different solvents (50% methanol, 50% ethanol, a 1:1 methanol-ethanol mixture, and distilled water) were used to extract the compounds. The extracts were then tested for total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (via 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay), and antimicrobial effects against Escherichia coli, Staphylococcus aureus, and yeast. The results showed that tray drying was more efficient in reducing moisture content, which is important for preserving the quality of the powder. UAE consistently outperformed conventional methods, particularly when used with methanol or the methanol-ethanol mixture, resulting in significantly higher levels of phenolic compounds and antioxidant activity. Among all combinations, tray drying followed by UAE using methanol produced the most potent antimicrobial effects. This study highlights the potential of repurposing pomegranate peel waste into functional ingredients for natural health products and food preservation. It also emphasizes the importance of selecting suitable drying and extraction techniques to ensure the recovery of high-value bioactive compounds, supporting both sustainability and innovation in food and nutraceutical industries.

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