Evaluation of Nutritional Composition and Antioxidants Properties of Onion (Allium Cepa) and Garlic (Allium Sativum)

Abstract

Two among commonly consumed spices all over the world, Onion (Allium cepa) and Garlic (Allium sativum) were examined for the proximate composition, mineral composition and antioxidant properties using standard methods. Proximate composition (%) of Allium Cepa and Allium Sativum were; moisture (16.23 ±0.1 and 12.14 ±0.05), crude fat (2.96 ±0.09 and 5.98 ±0.13), crude fibre (5.90 ±0.02 and 2.23 ±0.09), ash (5.58 ±0.02 and 3.71 ±0.01), crude protein (12.53 ±0.37 and 15.82 ±0.29), carbohydrate (58.67 ±0.56 and 58.25 ±0.84) and dry matter (83.77 ±0.08 and 87.86 ±0.05) respectively. The mineral composition (mg/100g) of the Allium cepa and Allium sativum respectively are; sodium (40.67 and 38.67), calcium (289.69 and 270.72), potassium (90.25 and 83.70), magnesium (8.33 and 7.90), iron (2.65 and 2.49), zinc (1.78 and 1.69), copper (0.67 and 0.52), manganese (0.61 and 0.55) while lead and cadmium were not detected in the samples. The result of the antioxidant properties showed that Allium cepa and Allium sativum contains; Total flavonoid (0.71 ±0.05 and 0.78 ±0.05) mg/g, total phenol (8.86 ±0.02 and 8.11 ±0.04) mg/g, Ferric Reducing Antioxidant Power (FRAP) (15.61 ±1.26 and 50.75 ±0.15) mg/g, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) (75.17 ±0.03 and 22.63 ±0.54) mg/g and Fe²⁺ chelation (30.28 ±0.46 and 38.07 ±2.29) mg/g respectively. The results revealed that the spices are good source of nutrients, minerals, and antioxidants. Therefore, their use as nutritional supplements is highly promising.