Antioxidant properties of cold-pressed black caraway, carrot, cranberry, and hemp seed oils

Cold-pressed black caraway, carrot, cranberry, and hemp seed oils were extracted with methanol and evaluated for radical-scavenging activities against ABTS+ and DPPH, chelating activity, oxygen radical absorbing capacity (ORAC), and total phenolic contents (TPC). All the oil extracts had significant antioxidant activities. The ORAC value ranged from 28 to 220 μmol TE/g oil for the cold-pressed hemp, carrot, and black caraway seed oils, whereas the ABTS+ - scavenging capacity ranged 8.9-30.8 μmol TE/g oil for the four cold-pressed edible seed oils. The greatest TPC, 3.53 mg gallic acid equivalent (GE) per gramme of oil, was detected in the cold-pressed black caraway seed oil extract, while the lowest TPC, 0.44 mg GE/g, was observed in the cold-pressed hemp seed oil extract. In addition, methanol extracts of the cold-pressed black caraway and cranberry seed oils were evaluated for their inhibitory capacities on human LDL oxidation by measuring the reduction of the thiobarbituric acid-reactive substance production (TBARS). Both oil extracts significantly suppressed the lipid peroxidation in human LDL, with TBARS reductions of 2.84 and 3.77 mg/g for cranberry and black caraway seed oil extracts, respectively. These results suggest that cold-pressed black caraway, cranberry, carrot and hemp seed oils may serve as dietary sources of natural antioxidants for health promotion and disease prevention, and the cold-pressed black caraway seed oil may be used as a natural antioxidative food additive for improving food quality and stability.