Valorization of functional properties of extract and powder of olive leaves in raw and cooked minced beef meat

BACKGROUND Olive leaves (OL), available in huge amounts from pruning, are known to be a useful source of biologically active compounds. This study investigated the potential application of OL as a supplement to minced beef meat in order to develop a functional product. The effect of OL extract or powder (100 and 150 µg phenols g−1 meat) on the quality and stability of raw and cooked meat during refrigerated storage was examined. RESULTS Microwave drying at 600 W gave OL with the highest antioxidant quality (evaluated by TEAC/[phenols] (mg mg−1) and DPPH/[phenols] (mg mg−1)) compared with other methods. OL showed an ability to inhibit (P < 0.05) lipid oxidation (TBARS values (mg MDA kg−1) were reduced by 25–65%) and myoglobin oxidation (metmyoglobin production was 43–65% in control samples and 14–35% in treated samples). OL also improved the technological quality of the meat, decreasing (P < 0.05) storage loss (%) and defrosting loss (%) without affecting cooking loss (%) and Napole yield (%). Sensory properties were not modified by the added ingredient at the tested levels (P < 0.05). CONCLUSION OL (extract or powder) may have applications in the development of functional meat products of good technological quality that remain stable during storage.