TITLE:
Physicochemical and Biochemical Characterization, Total Phenolic and Energy Value from Bulbs of Different Onion (Allium cepa L.) Varieties in Senegal
AUTHORS:
Ndeye Adiara Ndiaye, Lahat Niang, Modou Dieng, Ndeye Coumba Kane Touré
KEYWORDS:
Allium cepa L., Characterization, Physicochemical, Biochemistry, Total Phenolic
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.15 No.2,
February
21,
2024
ABSTRACT: The purpose of this study is to investigate the physicochemical
properties of some local varieties of onion (Allium cepa L.) and compare them with an imported variety, all
collected in May 2021. Proteins, reducing sugars, lipids, and polyphenol content were estimated according to
the AFNOR standardized methods. The determination of calcium, magnesium,
iron, sodium, potassium and phosphorus was performed by atomic absorption
spectrophotometer coupled with a CCD detector. The results highlighted an
average acidity of 0.377% ± 0.002% lower than the value of the imported variety
which is 0.520% ± 0.001%. Local varieties have a pH ranging from 6.35 ± 0.003 to 6.42 ±
0.004, while the variety has a pH of 6.36 ± 0.003. The ash and dry matter
contents vary respectively from 4.788% ±
0.004% to 8.253% ± 0.003% and 7.945% ±
0.021% to 11.945% ± 0.007% for the local varieties. Moreover, the imported one has ash and dry matter contents of 5.175% ± 0.007% and 10.035% ± 0.021% respectively. The results show that the protein, reducing sugar
and lipid contents in the local onion varieties vary respectively from 2.815 ±
0.000 to 15.634 ± 0.001 g·100 g-1; 4.691 ± 0.001 to 12.596 ± 0.002 g·100 g-1 and 0.006 ± 0.001 to 0.050 ±
0.057 g·100 g-1. Furthermore, the imported variety has a protein,
reducing sugar and lipid content of 5.649 ± 0.002; 8.565 ± 0.002 g·100 g-1 and 0.011 ± 0.010 g·100 g-1 respectively. The maximum levels
of total polyphenols are obtained in the imported variety, Bellani and Gandiol,
respectively 9.973 ± 0.001, 4.535 ± 0.002, and 3.425 ± 0.006 mg EAG/g of dry
matter. The local varieties have a significant calorific intake of between
35.451 ± 0.001 and 112.980 ± 0.003 kcal·100 g-1 compared to the imported one with
an energy value of 56.953 ± 0.001 kcal·100 g-1 of dry matter. The bulbs of
different onion varieties studied have a fairly high content of mineral
elements. The potassium content of local varieties is between 502.16 ± 0.06 mg·100 g-1 and 582.77 ± 0.04 mg·100 g-1 while the imported variety has a
content of 536.62 ± 1.30 mg·100 g-1. They note that the local varieties have a better
calcium content (249.75 ± 0.07 to 434.20 ± 0.57 mg·100 g-1) and magnesium (142.15 ± 0.07 to
162.60 ± 0.42 mg·100 g-1) than the imported variety (229.58 ± 0.04 mg·100 g-1) except for the varieties White
Grano (228.29 ± 0.01 mg·100 g-1)
and Rouge Amposta (117.00 ± 0.42 mg·100 g-1) respectively. These results reveal that Gandiol, Dayo
and Orient F1 are nutritionally found better due to their higher antioxidant
property, proteins, carbohydrates, and reducing
sugar and should be included in diets to supplement our daily allowance needed
by the body.