Food by-products as potential antioxidant and antimicrobial additives in chill stored raw lamb patties

The aim of this work was to study the in vitro antioxidant potential of aqueous extracts obtained from tomato (TOM), red grape (GRA), olive (OLI) and pomegranate (POM) by-products as well as to evaluate the effect of their addition into lamb meat patties (1000 mg/kg) in order to improve shelf life. A negative (CON) and a positive control (sodium ascorbate, ASC) were also included in the experiment. Results for radical scavenging activity, metal chelating activity and reducing power indicated that GRA and OLI extracts could inhibit oxidation more efficiently than POM and TOM extracts (P < 0.01). Consistently, GRA and OLI treatments showed the highest redness (a*) (P < 0.01) and antioxidant activity, both for lipids and proteins, throughout storage (P < 0.001). Furthermore, in general, microbial counts were reduced by the addition of by-products extracts. These results suggest that the extracts obtained from grape and olive pomaces could be effectively used to replace sodium ascorbate in lamb meat products.