Antioxidant activities of Moringa oleifera L. and Bidens pilosa L. leaf extracts and their effects on oxidative stability of ground raw beef during refrigeration storage

The study examined the leaf extracts of Moringa oleifera and Bidens pilosa for presence of bioactive phytochemicals and their antioxidant activities on pH and lipid oxidation of fresh ground beef during 6 days cold storage. The results revealed that B. pilosa leaf extract contained higher amount of bioactive compounds and antioxidant contents (p < 0.05) than M. oleifera leaf extract. The extract of B. pilosa leaf exhibited higher antiradical activity against 2,2-Diphenyl-2-picrylhydrazyl and 2,2íazino- bis-3-ethylbenzothiazoline-6-sulfonic acid radicals than M. oleifera leaf extract and standard butylated hydroxytoluene (BHT) (p < 0.05). Addition of M. oleifera and B. pilosa leaf extracts (0.5 and 1 g/kg) to fresh ground beef were found to lower the pH and thiobarbituric acid-reactive substances values compared with control and BHT treatments (0.2 g/kg) during the storage period (p > 0.05). The antioxidant activities of the extracts indicate that M. oleifera and B. pilosa leaf can be used as nutraceuticals or preservative agents in food industry.