Determination of Antioxidant Content and Capacity of Four Jordanian Fresh Citrus Fruits

H F Al-Sayyed,S M Abdel Qader,R A Al-Kurd,M M Mwalla

doi:10.5539/jas.v11n3p605

Abstract

Citrus fruits are considered one of the most grown crops worldwide including Jordan with high nutritive and non-nutritive value. The consumption of foods that contain natural antioxidants is thought to be an efficient way for reducing the risk for oxidative stress diseases. Determination of antioxidant content and capacity allows the screening of plants that are probably involved in the prevention and/or treatment of oxidative stress diseases. This study aimed at comparing four fresh Jordanian citrus fruits (namely: orange, lemon, pomelo, and mandarin) for their antioxidant content (using two methods namely: Folin-Ciocaltaeu method and total flavonoids method) and capacity (using two methods namely: 2,2-diphenyl-picrylhydrazyl (DPPH) and cupric antioxidant reducing capacity (CUPRAC) assays). Three solvents were used for the fruit extraction (ethanol, methanol, and water). There were significant (P &lt; 0.05) differences between the fruits in terms of antioxidant content and capacity. Regardless of the extraction solvent, the fruit content of total polyphenols (M catechin/100 g) was as follows: lemon &gt; mandarin &gt; pomelo &gt; orange. The total flavonoid content (mM rutin/100 g) of the fruits was: orange &gt; mandarin &gt; lemon &gt; pomelo. On the other hand, the antioxidant capacity (M trolox/100 g) of the fruits was: lemon &gt; mandarin &gt; orange &gt; pomelo. The antioxidant capacity (measured as mg vitamin C/ml extract) of the fruits was: mandarin &gt; orange &gt; pomelo &gt; lemon. Different extracts of different fruits showed significantly (P &lt; 0.05) different antioxidant contents and capacities. No correlation between antioxidant content and antioxidant capacity of the studied fruits has been found.

Highlights

Fruits and vegetables are considered of the most important natural sources of antioxidants (Apak et al, 2007)
Methanol had extracted the highest amounts of antioxidants from pomelo
No correlation has been found between any of the studied parameters. This probably implies that there are antioxidants other than those analyzed by the researchers that might have contributed to the antioxidant capacity values shown in Tables 3 and 4

Summary

Introduction

Fruits and vegetables are considered of the most important natural sources of antioxidants (Apak et al, 2007). Citrus fruits are considered one of the most grown crops worldwide, including Jordan, with high nutritive and health values. The health benefits of citrus fruits have been attributed mainly to the presence of antioxidants such as phenolics and ascorbic acid (Kumar, Lamers, Singh, Ladaniya, & Sthapit, 2015). Oxidative reactions are considered important because they might lead to imbalanced oxidative status of a living cell and to oxidative stress diseases . Many chronic diseases are thought to have oxidative stress background in their pathogenesis. The consumption of antioxidants is thought to reduce the risk for oxidative stress diseases (Halliwel & Gutteridge, 1995)

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Conclusion