Yousif A. Elhassaneen^1,, Lamiaa A. Diab¹, Esraa S. ElFaramawy¹

Meat and meat products are extremely nutritious but highly susceptible to deterioration because of lipid oxidation and protein degradation in addition to microbial growth which contributes to deterioration of the products as time goes by. This paper determined the efficacy of the chosen plant extracts and agro-industrial by-products as natural antioxidants and antimicrobials in beef meatballs. The meatballs were prepared using 78% minced beef, 14.5% potato flakes, having 5 % water, 2.5% salt and 0.25% of each extract or mixtures of extracts were added. The results of antioxidant activity indicated that carnation flower extract registered the best activity (AOX, 0.027, AA, 92.75, AAC, 1157.04) and rosemary (AA, 68.54) and peach kernels (AA, 85.01), and mixtures registered a better performance (Mix1 AA, 93.21, AAC, 1165.04). Total phenolic content varied between carnation (174.70 mg GAE/g) and tomato pomace (16.98 mg GAE/g), and there was a significant correlation between phenolics and antioxidant activity (r 2 = 0.5364). In the β-carotene test, samples treated recorded lesser oxidation than control, verifying the efficacy of an antioxidant. When kept in refrigerated conditions (4°C, 12 days), the control samples increased in TBA concentration sharply (0.33 to 4.71mg/kg), but in treated samples, the value was lower, especially in Mix 1 and Mix 2 (0.95 and 1.00 mg/kg). Protein degradation was also on the same trend, whereas the control TVB-N rose to 6.79 and 15.16 mg/100 g, mixtures remained lower (10.67 and 10.28 mg/100 g). Microbial growth was also prevented, the counts of LABs grew to 4.79 log cfu/g in control, but remained substantially lower in Mix1 and Mix2 (2.01 and 2.19 log cfu/g). Sensory acceptability was reduced in all samples but maintained better in treatment groups with mixtures experiencing the least (approximately 22%). These results prove that the plant-based extracts particularly in synergy are helpful in enhancing the oxidative stability, reducing spoilage and increasing the shelf life of meat products. The improvements that were observed were related to the difference in phenolic composition and extract type where pomegranate and onion skin extracts also showed significant effects with TBA value about 1.21-1.22 mg/kg and TVB-N at around 11.00 mg/100 g. Meanwhile, individual extracts had a moderate protection over mixtures, which mean that there was variation in the efficacy between the sources. In general, findings support the possibility of using natural extracts as a substitute of synthetic preservatives in the meat systems during storage.

Onion skin, tomato pomace, coriander seeds, rosemary leaves, carnation flower, cumin seed, pomegranate skin, peach kernels, shelf life, total volatile base-nitrogen, microbial growth