Antioxidant capacity of phenolic phytochemicals from peel of apples, pears, plums, red and white grapes

Polyphenolic phytochemical extractions from peel of apples, pears, plums, red and white grapes were performed using 70% ethanol and 0.9% NaCl (7:3) with ultrasound assistance and extracts were analyzed for total phenolics, flavonoids, and antioxidant capacity. In the tested fruit the highest content of flavonoids was found in the red grapes (4.337±0.218mg/g), followed by the pear and the plum (3.333±0.035 and 3.108±0.157mg/g), which have almost identical content, and the white grapes and the apples which again have an approximately equal content of flavonoids (2.126±0.039 and 2.072±0.096mg/g). The antioxidant capacities of analysed fruit extracts were assayed for antioxidant activity by DPPH radical scavenging and total reducing power. The percentage of neutralize DPPH radicals can be reported by EC50 value or by the concentration of extract required to neutralize 50% of DPPH radicals. The lowest EC50 value, and therefore the highest antioxidant activity was in the extracts of red grape, followed by the extracts of pear, apple, white grape, and plum.The highest content of phenolic compounds were in extract of the red grape (12,884±0,444mg/g), than followed by the pear (9,590±1,031mg/g), the plums (9,296±0,268mg/g), the apples (3,676±0,135mg/g), and the lowest content was in the extract of the white grapes (3,009±0,161mg/g).

Acknowledgement: This work was supported under the projects No.OI 45001 by the Ministry of Science of the Republic of Serbia.

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