Sustainable utilization of olive leaves and pomace as sources of fatty acids and bioactive compounds

Olive leaves and pomace are being wasted in Pakistan and remain unexplored concerning their bioactivity and fatty acids. The objective of the present work is to study fatty acids and antioxidant potentials of olive leaves and fruit pomace indigenous to Pakistan. The antioxidant potential of both water extract (WE) and ethanol extract (EE) of olive leaves and fruit pomace was also investigated. Results showed that olive leaves exhibited the highest oleic acid content (54.60%±3.40%), followed by palmitic acid (15.20%±1.20%). For olive pomace, oleic acid was the most abundant fatty acid (59.30%±2.40%), while palmitic acid and linoleic acid were recorded at 6.30%±0.56% and 5.2%±0.61%, respectively. However, oleic acid (59.30%±2.40%) was present in the highest quantities in olive pomace, followed by palmitic acid (6.30%±0.56%) and linoleic acid (5.20%±0.61%). The EE of olive leaves had higher total phenolics (1902.00±189.00 mg GAE/100 g) than WE (1216.00±143.00 mg GAE/100 g). The WE of olive pomace had higher total phenolics (292.40±18.00 mg GAE/100 g) than EE (201.80±15.00 mg GAE/100 g). The scavenging activity of DPPH of ethanol-soluble extracts (EE) (60.60±3.50 µM TE/g) of olive leaves was also greater than their respective water-soluble extracts (WE) (51.20±3.00 µM TE/g). Similarly, scavenging activity of ABTS of EE (9.88±0.90 µM TE/g) of olive leaves was greater as compared to WE (3.24±0.40 µM TE/g) of leaves. The DPPH radical scavenging activity of EE (29.44±1.10 µM TE/g) of olive pomace was higher than its respective WE (14.24±1.40 µM TE/g). However, the ABTS scavenging activity of EE (6.05±0.90 µM TE/g) of olive pomace did not vary significantly (p<0.05) with regard to its respective WE (5.99±0.45 µM TE/g). Results concluded that olive leaves and olive pomace are good sources of fatty acids and antioxidants, which are recommended in food application according to a sustainable approach strategy.