Total Phenolic Content and Antioxidant Capacity of Fruit Juices

Abstract

The interest in polyphenolic antioxidants has increased remarkably in the last decades due to of their elevated capacity in scavenging free radicals associated with various human diseases. Previously, some fruits were shown to contain high antioxidant activities. Fifteen fruit juices were analyzed for total phenolic content and antioxidant capacity (oxygen radical absorbance capacity, ORAC). The total phenolic content (TPC) was measured by Folin-Ciocalteu assay and gallic acid used as standard. TPC varied from 7.3 mg GAE/100 mL for aloe vera juice to 71.8 mg GAE/100 mL for cranberry juice. The value of antioxidant capacity was determined by ORAC test, using 2,2'-azobis(2-amidino-propane) dihydrochloride as reactive species and Trolox as a standard. Obtained values were from 27.1 μmol TE/100 mL for aloe vera juice to 1271.8 μmol TE/100 mL for black currant juice. Results from the present study suggest further analysis on chemical composition of samples in order to identify compounds that might be responsible for antioxidant activity.