Assessment of Nutritional Properties from Six Varieties of Onion (Allium cepa L., Alliaceae) Produced in Northern Côte d’Ivoire

Abstract

Aims: Onion is a common vegetable engaging significant nutritional interests and widely consumed over the world. In Côte d'Ivoire, 95% of the onion consumption is filled by imports despite the availability of suitable areas for its local production. The current study aimed to investigate nutritional features of onion varieties for fitting the agronomical trends in order to strengthen the onion cultivation in northern Côte d’Ivoire. Study Design: Six onion varieties produced for bulbs, namely ARES, BATI, CARA, DAMANI, KARIBOU, and SAFARI. Onion bulbs sampled, oven-dried, and then processed to powders for analysis. The main study consisted in analyzing the biochemical properties of the resulted onions powders. Place and Duration of Study: Experimental farming from the plants experimenting location, and onion samples analyzed from Laboratory of Peleforo Gon Coulibaly University, Korhogo, Côte d’Ivoire, between March 2020 and April 2021. Methodology: Batches of 2 kg fresh bulbs collected per onion variety after harvest. Once at Lab, onion bulbs peeled, washed, cut into small dice-shaped pieces and dried into an oven at 80 °C for 24 h using stainless trays. Dried samples ground and kept for analyses regarding physicochemical traits (moisture, acidity, ash) and nutritive parameters (glucides, lipids, proteins, antioxidants). Results: The works showed higher contents in moisture (16.91%), ash (4.46%), and lipids (1.99%) from CARA variety with more significant acidity; while greatest amounts of total soluble carbohydrates (14.5%), tannins (1.02%), and proteins (13.6%) were recorded from BATI and more vitamin C in DAMANI (0.133%). However, SAFARI variety samples were more provided in reducing carbohydrates (1.04%) and total polyphenols (1.46%) as secondary metabolites; and the ARES variety revealed highest flavonoids contents (0.057%). In addition, ARES, CARA, and KARIBOU varieties displayed great dietary fibers amounts compared to BATI, KARIBOU, and SAFARI. Conclusion: The particular nutritional traits of the studied onion varieties could be confronted with their agronomical yield and consumption trends for supporting sustainable production of onion in Côte d’Ivoire.