ORIGINAL RESEARCH
Biochemical Characterization of Local Onion
Genotypes (Allium cepa L.)
in the Arid Regions of Tunisia
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1
Faculty of Sciences of Gabès, Tunisia
2
Dryland Farming and Oasis Cropping Laboratory (LR16IRA02), Arid Lands Institute, Médenine, Tunisia
3
Regional Research Centre on Horticulture and Organic Agriculture (CRRHAB),
LR21AGR03, University of Sousse, Tunisia
4
Agrifood Research and Technology Centre of Aragon (CITA). Zaragoza, Spain
5
AgriFood Institute of Aragon – IA2 (CITA-University of Zaragoza), Zaragoza, Spain
Submission date: 2022-02-02
Final revision date: 2022-05-07
Acceptance date: 2022-07-04
Online publication date: 2022-12-05
Publication date: 2022-12-21
Corresponding author
Samir Tlahig
Arid Land Institute of Médenine, El Fjé- Km 22, 4119, Médenine, Tunisia
Pol. J. Environ. Stud. 2023;32(1):15-26
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ABSTRACT
Nineteen Tunisian onion genotypes were characterized based on phytochemical composition,
sugar content, and antioxidant activity. The studied onions showed a great diversity on biochemical
contents and composition. It seemed that there were differences between genotype categories (local
landraces or local breeding lines) and within the same category. Quercetin and quinic acid were,
respectively, the main flavonoid (flavonol) and organic acid (cyclitol) identified and quantified by HPLC.
In all studied onions, quercetin was the predominant flavonoid, with the highest content in the local
breeding line OP2-w (1142.19 mg 100 g-1 DW). OP3-w showed the highest value of total phenolic as
well as total flavonoid content at 12.52 mg GAE g-1 DW and 48.28 RE g-1 DW respectively. Fructose
and sucrose were the most abundant sugars in all the genotypes. Clustering and PCA analysis showed
a great dispersion of these genotypes which were classified into 3 major groups. The chemical and
nutritional composition found highlights the great value of this onion germplasm which can be used for
the sustainable conservation and management of Tunisian onion genetic resources.