Onion (Allium cepa L.) Skin Waste Valorization: Unveiling the Phenolic Profile and Biological Potential for the Creation of Bioactive Agents through Subcritical Water Extraction

• Type: Article in International Scientific Journal
• Date: 2024

Authors

Trigueros, E (Author) Other; Benito-Román, O (Author) Other; Oliveira, AP (Author) Other; Videira, RA (Author) Other; Paula B Andrade (Author) FFUP; Sanz, MT (Author) Other; Beltrán, S (Author) Other

Journal

Title: Antioxidants

Vol. 13

Final page: 205

ISSN: 2076-3921

Publisher: MDPI

Indexing

ISI Web of Knowledge - 0 Citations

Scopus

Other information

Authenticus ID: P-010-2B3

DOI: 10.3390/antiox13020205

Abstract (EN): Onion skin waste (OSW), the primary non-edible byproduct from onion processing, offers a renewable source of bioactive compounds. This study aims to valorize OSW through subcritical water extraction (SWE), aligning with a circular economy and biorefinery principles. SWE was carried out at 145 degree celsius and 50 bar for 50 min in a discontinuous reactor, producing a phenolic-rich extract (32.3 +/- 2.6 mg/g) dominated by protocatechuic acid (20.3 +/- 2.5 mg/g), quercetin-4'-O-glucoside (7.5 +/- 0.2 mg/g), and quercetin (3.2 +/- 0.6 mg/g). Additionally, the extract contains sugars (207.1 +/- 20.3 mg sucrose-Eq/g), proteins (22.8 +/- 1.6 mg BSA-Eq/g), and free amino acids (20.4 +/- 1.2 mg arginine-Eq/g). Its phenolic richness determines its scavenging activity against (NO)-N-center dot and O-2(center dot-) radicals and its alpha-glucosidase and aldose-reductase inhibition without affecting alpha-amylase. Notably, the extract demonstrates significant alpha-glucosidase inhibition (IC50 = 75.6 +/- 43.5 mu g/mL), surpassing acarbose (IC50 = 129.5 +/- 1.0 mu g/mL) in both pure enzyme and cell culture tests without showing cytotoxicity to AGS, HepG2, and Caco-2 human cell lines. The extract's bioactivity and nutritional content make it suitable for developing antioxidant and antidiabetic nutraceutical/food components, highlighting SWE's potential for OSW valorization without using organic solvents.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 18