Comparison of lipid radical scavenging capacity of spice extract in situ in roast beef with DPPH and peroxy radical scavenging capacities in vitro models

The effects of 7 spice extracts on lipid radical formation were first collectively studied in situ in roasted beef by electron spin resonance (ESR). And the correlations among the ESR and conventional indexes including 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging capacity, reducing power, oxygen radical absorption capacity (ORAC), conjugated diene value (CDV) and thiobarbituric acid-reactive substances (TBARS) were also analysed. Clove was observed the highest scavenging lipid radical and DPPH radical capacity, and rosemary showed the highest peroxyl radical scavenging capacity, while tert-butylhydroquinone (TBHQ) significantly increased lipid radicals in roasted beef ( p  < 0.05). ESR showed significant correlations with the DPPH and CDV assays ( p  < 0.05) but no correlation with the ORAC and TBARS assays ( p  > 0.05), indicating that with the addition of spice extracts, the lipid radical formation in roasted beef could be predicted by the DPPH assay but not be appropriate to evaluate the oxidation stability in roasted beef.