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Nutrients and antioxidant properties of red, yellow and white onions (Allium cepa L) in Ibadan, Oyo State, Nigeria


I.F. Ani
T Alfa
A.S. Kupoluyi
A.S. Kupoluyi

Abstract

Background: Onions is the most widely consumed vegetable worldwide and is a rich source of phytochemicals and antioxidants responsible for fighting free radicals in the body and preventing diseases


Objective: The general objective of the study was to analyze and compare the nutrient and antioxidant properties of red, yellow and white onions in Oyo state, Nigeria.


Materials and Methods: The research design was experimental. Samples were analyzed chemically according to the official method of analysis described by the Association of Official Analytical Chemist (AOAC). All analysis was carried out in triplicate. Data was analyzed using IBM SPSS statistics version 20. ANOVA was used to compare different variables together.


Results: The protein content was same in red and white onions. The crude fibre for red onions was 1.1 ±0.12, yellow onions 1.4±0.08 and white onions 1.2 ±0.12. White Onions had the highest total ash content (0.8 ±0.08), followed by yellow onions (0.6 ± 0.08) and red onions (0.6 ±0.05). The carbohydrate (by difference) was 12.2 ±0.09 for red onions, 11.1 ±0.22 for yellow onions and 11.4 ±0.36 for white onions. The reducing sugars for red onions was 1.8 ±0.12, yellow onions had 1.1 ±0.08 while white onions contained 1.2 ±0.12. The total sugars for red onions, yellow and white onions were 2.6 ±0.12, 1.7 ±0.12 and 2.2 ±0.12 respectively. The ascorbic acid (mg/100g) content was 15.8 ± 0.79 for red onions, 11.2 ±0.21 for yellow onions and 12.4 ±0.53 for white onions. Quercetin (mg/g) was highest in red onions (0.32 ±0.02), followed by yellow onions (0.24 ±0.01) and then white onions (0.19±0.01).  


Conclusion: The nutrients and antioxidant (quercetin and vitamin c) properties were higher in red onions compared to the other varieties (white and yellow) of onions.


Journal Identifiers


eISSN: 2635-3326
print ISSN: 2141-8209