Evaluation of Antioxidant and Free Radical Scavenging Abilities of some Nigerian Packaged Fruit Juices
AbstractObjective: This study was aimed at determining the antioxidants and free radical scavenging abilities of some packaged fruit juices (PFJ) widely used as source of fluids in Nigeria. Materials and methods: Packaged fruit juice samples produced by The Coca cola Company and Chi company namely: Apple(AP), blackcurrant, grape raspberry and Strawberry(Blackcurrant juice, BB), Guava(GU), Mango and Orange (MO), Orange(OR), Orange / Peach(OP), Orange, lemon, grape ,tangerine and lime (Citrus burst, CB), Pineapple (PA), Pineapple /Coconut (PC) and Lemon / lime(LL); were purchased from retail shops in Benin City, Nigeria. Total polyphenolic content was measured by the Folin–Ciocalteau and in vitro antioxidant capacity using four different assay methods namely1,1,-diphenyl-2-picrylhydrazyl [ DPPH] and 2,2-azinobis(3-ehtylbenzothiazoline-6-sulfonic acid) [ABTS] radical ion scavenging abilities, ferric ion reducing antioxidant power (FRAP) and iron (Fe2+) chelationassays. Results: The results revealed that, Guava juice contained the highest amount of total phenolics (32.25 ±1.25mg/100ml gallic acid equivalents), and Vitamin C (26.55 ± 0.003mg/100ml).The highest amounts of total flavonoids was found in the citrus burst (14.65 ±3.04mg/ 100ml quercetin equivalents). Blackcurrant juice had the highest abilities to scavenge DPPH radical (53.55±10.88 %) and chelate iron (26.92 ±1.36 %) from solutions. Guava juice had the highest amount of ferric reducing antioxidant property (353.00mg/100ml). Correlation studies showed that, total phenol were positively correlated with vitamin C ( r = 0.71), reducing property (r = 0.96), ABTS (r = 0.52) and DPPH assays (r = 0.65). Generally, the antioxidant scavenging abilities were positively correlated with the antioxidants present in the fruit juices. DPPH scavenging ability was positively correlated with total phenol(r =0.65), total flavonoid (r = 0.544), vitamin C (r = 0.43), reducing property (r = 0.64) and ABTS (r = 0.48). However, iron chelating ability was negatively correlated at p≤ 0.05 with the antioxidants present in the juices studied Conclusion: Guava, blackcurrant and citrus burst fruit juices demonstrated high antioxidant content and free radical scavenging abilities. Orange, Pineapple/ coconut, lemon /lime fruit juices ranked low in the antioxidant content and radical scavenging abilities, but had high iron chelation ability. These package fruit juices contain antioxidants that can diminish the harmful effect of free radicals. Keywords: Fruit juices, antioxidant content, free radical scavenging ability
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