Phytochemical Constituents and Antioxidant Activity of Artemisia Afra and Bidens Pilosa Essential Oil in Ground Pork

The study examined essential oils (EO) extracted from Artemisia afra and Bidenspilosa leaves for bioactive phytochemicals and their antioxidant activities on pH and lipid oxidation of ground porkduring cold storage. Artemisia afra and B. pilosa EO were extracted by solvent-free microwave extraction. Phytochemical profiles and antioxidant activities were determined by gas chromatography-mass spectrometry and free radical scavenging (DPPH) respectively. Fresh pork was purchased, minced and treated with either A. afra EO (0.2 ml/ 100 g), B. pilosa EO (0.2 ml/100 g), A. afra + B.pilosa (0.2 ml/100 g) or synthetic antioxidant (BHT, 0.02 % w/w) and stored for 7 days (4 +/- 1 degrees C). The pH and thiobarbituric acid reactive substances (TBARS) of the meat samples were analyzed on day 1 and 7. The A. afra EO had a higher amount of phytochemicals (86 compounds) than B. pilosa (25 compounds).The major bioactive components in theEO which have been reported for antioxidant and antimicrobial activities include eucalyptol (16.62 %), caryophyllene oxide (0.38 %), bicyclogermacrene (0.72 %), caryophyllene (1.70 %), bicyclo[2.2.1]hept-2-ene, 1,7,7-trimethyl (0.35 %), bornyl acetate (0.68 %), camphor (15.2 %), endo-borneol (2.23 %), terpinen-4-ol (1.93 %), 3,5-dimethylcyclopentene (0.67 %), alpha-terpineol (0.55 %) and artemiseole (0.23 %).The DPPH values of A. afra were higher than B. pilosa but comparable with reference standard. The TBARS in meat samples treated with A. afra and B. pilosa leaf EO tended to be lower (p> 0.05) compared to control and BHT treatments during the storage period. In conclusion, A. afra EO exhibited higher antioxidant compounds and activity to inhibit lipid oxidation in ground pork during cold storage (4 degrees C).