Phytochemical and antioxidant properties of fresh fruits and some traditional products of wild grown raspberry (Rubus idaeus L.)

Abstract

The current study investigated and compared phytochemical and antioxidant activity of fresh fruit and some traditional products of Rubus idaeus grown in mountain region of Serbia. The total organic acid, total sugar content, total phenolics, flavonoids, tannins, anthocyanins and vitamin C were evaluated. The antioxidant activities were evaluated using two antioxidant systems 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The fresh fruit contained highest amount of vitamin C (46.62 mg AA g -1 ) and total organic acids (882.22 mg CA g -1 ). The sweet preserve had highest content of total phenolics (200.83 mg GA g -1 ), flavonoids (12.85 mg RU g -1 ) and tannins (39.11 mg g -1 ). The juice had the highest total anthocyanin content (107.22 μg mL -1 ) and total sugar content (25 °Brix). The best antioxidant activity in ABTS assay had juice (IC 50 = 4.87 μmol TE g -1 ), followed by sweet preserve (IC 50 = 5.14 μmol TE g -1 ), almost identical to standard gallic acid. In the DPPH free radical scavenging assay, sweet fruit preserve showed significant better antioxidant activity (IC 50 = 41.27 μg mL -1 ) compared to juice (IC 50 = 106.07 μg mL -1 ) and fresh fruit (IC 50 = 294.79 μg mL -1 ). Our results indicated promising perspectives for usage of R. idaeus fresh fruits and traditional products studied with considerable levels of vitamin C, bioactive compounds and antioxidant activity.