Total Flavonoids, Total Phenolics And Vitamin C: Indicators Of The Antioxidant Potentials Of Selected Fruit Peels
The environment has been dumped with various solid wastes. A good part of this kind of wastes are the peels from fruits. Recent scientific researches have discovered the worth of the fruit peels in terms of substances that are good for the health. This study determined the antioxidant properties in terms of total flavonoids, total phenolics and vitamin C of the methanolic extract of the ten (10) selected fruit peels, namely, rambutan (Nephelium lappaceum), mango (Mangifera indica), marang (Artocarpus odoratissimus), santol (Sandoricum koetjape), soursop (Annona muricata), lakatan (Musa sapientum), avocado (Persia americana), lanzones (Lansium domesticum), watermelon (Citrullus vulgaris) and dragon fruit (Hylocereus undatus). Quantitative analysis showed that lanzones had the highest total flavonoids (213.45 mg quercetin/g dried material). Rambutan was high in both vitamin C (36.47 mg ascorbic acid/g dried material) and total phenolics concentration (96.69 mg GAE/g dried material). Dragon fruit came out with the lowest total flavonoids (5.70 mg quercetin/g dried material) and total phenolics (0.66 mg GAE/g dried material); no vitamin C was detected. Flavonoids, phenolics and vitamin C are recognized antioxidants. Analysis of the 10 selected fruit peels showed the total flavonoids content to have this order (highest to lowest concentration) – lanzones > santol > rambutan > marang > watermelon > mango > lakatan > avocado > soursop > dragon fruit. In terms of total phenolics, rambutan > mango > santol > marang > lanzones > soursop > lakatan > watermelon > avocado > dragon fruit. For vitamin C, rambutan > lanzones > lakatan > watermelon > soursop > marang > mango > avocado > santol > dragon fruit.
Keywords— Antioxidants, Total Flavonoids, Total phenolics, Vitamin C, Fruit peels.