Profiling of valuable bioactive metabolites and characterization of water chestnut (Trapa natans L.) peel powder using High-Resolution Mass-Spectrometry

• Water chestnut peel is rich in phenolics and flavonoids • Blanching enhances the release of bioactive compounds • Quercetin, ferulic acid, phloretin and limonin were present • Bioactive compounds, making it a promising functional food ingredient Water chestnut ( Trapa natans L.) peels is an ill-defined and underutilized by-product of agri- food industry. These peels are rich source of bioactive constituents, mainly polyphenols and flavonoids that can be extracted using various sustainable green methods. This study aims to investigate bioactive compounds present in water chestnut peel and their characterization. Blanched ethanol extract was shown to have higher flavonoid content (13.28 mg CE/g) total phenolic content (78.20 mg GAE/g), (% DPPH inhibition, 41.08 ± 0.52) and ABTS (61.69 ±0.52 %) suggesting that heat pretreatment enhances the release of bioactive components. Phenolic, flavonoid, and lignin-related functional groups were detected by FT-IR peak analysis. In XRD 2θ represents the total angular separation between the incident X-ray beam and the diffracted beam from the crystal planes. The presence of 2θ degrees of 14-20 in the peaks of XRD was linked to flavonoids including gallic acid, kaempferol, and quercetin. A wide range of major secondary metabolites, including as quercetin, ferulic acid, phloretin, limonin, 18-β-Glycyrrhetinic acid, prunin, gallic acid, and linoleamide were discovered. The results of this study revealed that blanched peel with ethanol extraction method yielded best results and also be exploited an inexpensive source of natural ingredients for functional foods.