Antioxidant activities of ethanol extracts from seeds in fresh Bokbunja (Rubus coreanus Miq.) and wine processing waste

The antioxidant potential of ethanol extracts from defatted Bokbunja seed wastes generated during wine processing were estimated by radical scavenging abilities (DPPH, H2O2, and O2-), retardation of lipid oxidation, and iron ion-chelating characteristics. For comparison, ethanol extracts from seeds of fresh ripe Bokbunja fruits were also used. The ethanol extracts from the wine seed waste always showed higher scavenging activities against DPPH, H2O2, and O2- than those from the fresh seeds. The oxidation of linoleic acid in dimethylsulfoxide at 105 °C revealed that the kinetic behavior clearly obeyed pseudo-zero-order regardless of the linoleic acid concentration. The Fe(II)-chelating capacity was determined by the Freundlich isotherm. The results showed high potential and favorability of the two extracts for Fe(II) chelation. The Freundlich chelation capacities (mg1−1/n L1/n/g) of both ethanol extracts from seeds of fresh Bokbunja and wine processing wastes, tannic acid, and proanthocyanidin from Pinus radiata bark were 100, 224, 260, and 307, respectively. The Fe(III)-chelating properties of the ethanol extracts were considered to be deeply associated with its 3′,4′,5′-trihydroxyl (galloyl) group as with tannic acid.