Yousif A. Elhassaneen^1,, Ghada M. ElBassouny², Rania H. Hassan², Eman B. Meharam²

The present work was carried out to study the antioxidant activity of natural products (onion skin, potato peel, marjoram, fennel, cinnamon, black seed and olive leaf) in relation to their content of total phenolic compounds. Also, their aqueous extracts will be applied in meatballs to prevent chemical and bacteriological spoilage agents and extend its storage life within the scope of this investigation. Such data indicated that the natural products extract showed considerable differences in antioxidant activity (AA= 61.83 to 92.75%) and total phenolics content (297.94 to 1207.32 mg of GAE.100g^-1). When all extracts were included in the statistical analysis, there was a positive [Total phenolics (mg/100g, d.b.)= 23.083 (Antioxidant activity, %) –1082.4, r²= 0.6306] and significant (p≤ 0.01) relationship between total phenolics and antioxidant activity. Activity in a lamb fat system was established for all the extracts and further determination of the development of rancidity as malonaldehyde consistently showed that more that 50% of the rancidity can be controlled by the onion skin, potato peel, cinnamon, black seeds preparations after a period of 12 days of storage at 4°C. The same behavior was recorded for the protein quality parameter, total volatile-base nitrogen (TVBN). Also, such extracts activity against lactic acid bacteria was demonstrated in an agar diffusion test in the product and its counts were significantly (p<0.05) reduced. Sensory analysis results, particularly acceptability scores, indicated the significant advantages in using all extracts in rancidity-susceptible meat products. Furthermore, the use of mixtures of these extracts gave more effective results compared to the use of extracts in a single way, which proves the interactional effects of the different groups of bioactive compounds contained in those extracts in the case of mixing. Finally, the results of the study are an important step for using these natural extracts in the food industry as a substitute for synthetic antioxidants, especially after suspicions have been raised about the harmful and devastating effects of these chemically synthesized compounds on public health.

plant parts, malonaldehyde, total-base volatile nitrogen, lactic acid bacteria, acceptability scores