Effectiveness of manuka and rosemary oils as natural and green antioxidants in wagyu and normal beef

Essential oils possessing antioxidant characteristics have acquired broad interest as an alternative to synthetic food antioxidants like butylated hydroxytoluene (BHT). In this study, manuka (with 5, 25 and 40% triketone content) (MO), rosemary (RO) and kanuka (KO) oils were characterised and screened through DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (Ferric radical absorbing power) assays for their antioxidant efficacies. Different triketone levels were selected to examine their effect on the antioxidant activity of MO. All MOs showed higher phenolic content and antioxidant activities than KO and RO. Based on the obtained results, the MO with 25% triketone content and RO were chosen to study their antioxidant effects in pastes prepared from New Zealand normal (3% fat) and wagyu (12% fat) beef during refrigerated storage (7 days). No significant effect of the oils was observed on lipid oxidation in normal pastes during storage. However, MO and BHT significantly reduced lipid oxidation in wagyu pastes, showing the potential of manuka oil as a natural antioxidant in high-fat meat products.