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ORIGINAL RESEARCH article

Front. Sustain. Food Syst.
Sec. Waste Management in Agroecosystems
Volume 8 - 2024 | doi: 10.3389/fsufs.2024.1469635
This article is part of the Research Topic Agri-Food Waste Utilization for Sustainable Future: Challenges and Opportunities View all 6 articles

Characterization and Evaluation of Antioxidant Potential of Onion Peel Extract of Eight Differentially Pigmented Short-Day Onion (Allium Cepa L.) Varieties

Provisionally accepted
Kalyani Gorrepati Kalyani Gorrepati 1*Ashok Kumar Ashok Kumar 1*Ahammed Shabeer TP Ahammed Shabeer TP 2Zareen Khan Zareen Khan 2Prashant Satpute Prashant Satpute 1Sivalingam Anandhan Sivalingam Anandhan 1Thangasamy Arunachalam Thangasamy Arunachalam 1Vishwanath R. Yalamalle Vishwanath R. Yalamalle 1Vijay Mahajan Vijay Mahajan 1Major Singh Major Singh 1
  • 1 Directorate of Onion and Garlic Research (ICAR), Pune, India
  • 2 National Research Centre for Grapes (ICAR), Pune, Maharashtra, India

The final, formatted version of the article will be published soon.

    Outer papery peel of onion bulb is an inevitable bio-waste generated in the course of postharvest handling and processing. Onion peels are rich source of nutraceutically important polyphenolic compounds having many therapeutic potentials. Here, we characterized onion peel extract (OPE) of eight differentially pigmented short-day onion varieties through ultrahigh-performance liquid chromatography coupled with high resolution single stage Orbitrap spectrometry and evaluated the antioxidant potential. Total 49 phenolic compounds were identified in this study which includes 33 anthocyanin, 08 flavanol, 04 flavones and one each of pyranoanthocyanin, chalcone, phenolic acid, and ellagiotannins. Anthocyanin was the most abundant polyphenolic compound followed by flavanol in all the varieties. Among anthocyanin, 10 cyanidin, 10 delphinidin, 4 peonidin, 4 petunidin, 3 pelargonidin, and 2 malvidin were identified. Cyanidin-3-(6-malonylglucoside), delphinidin and delphinidin-3galactoside were the predominant pigment in dark red varieties (BDR and BRJ) and its abundance suggests a key role in the differential pigmentation pattern of onion peel. Total phenol content (TPC) in peels ranged 1738.21-1757.76 mg GAE/100g DW in dark red onion, 1306.58-1646.73 mg GAE/100g DW in red onion, and 78.77-85.5 mg GAE/100g DW in white onion varieties. The mean total anthocyanin content was maximum (28.23 mg/100g DW) in dark red varieties (BDR) and minimum (0.11 mg/100g DW) in white variety (BSW).Total antioxidant activity was ranged 4.71-79.80 µmol/g DW, 22.71-286.7 µmol/g DW and 8.72-156.89 µmol/g DW estimated through FRAP, ABTS, and DPPH methods respectively. In all three methods, it was maximum in dark red var. BDR and minimum in white var. BSU.

    Keywords: antioxidant, Anthocyanin, Flavonoids, Onion peel extract, Quercetin

    Received: 24 Jul 2024; Accepted: 18 Oct 2024.

    Copyright: © 2024 Gorrepati, Kumar, Shabeer TP, Khan, Satpute, Anandhan, Arunachalam, Yalamalle, Mahajan and Singh. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Kalyani Gorrepati, Directorate of Onion and Garlic Research (ICAR), Pune, India
    Ashok Kumar, Directorate of Onion and Garlic Research (ICAR), Pune, India

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.