دراسة إمكانية حفظ لحم الدجاج المخزن بالتبريد باستخدام المستخلص الإيتانولي لأوراق نبات القراص

Abstract

This study aimed to determine the phenolic content and antioxidant activity of the leaf extract of the plant Urtica dioica. Additionally, the effect of treating fresh chicken breast meat with ethanolic (70%) leaf extract of Urtica dioica plant was studied in terms of chemical and microbiological indicators during refrigerated storage at a temperature of (4±1°C) for a duration of (16) days. Chicken breast meat samples were treated with concentrations of (0, 1, 3, 5, 7%) of the extract. The phenolic content of the extract was found to be (213.9 mg/g), and it exhibited good antioxidant activity with an inhibition percentage (I%) (41.45%). The treatments showed a significant decrease in thiobarbituric acid reactive substances (TBARS) values compared to the control sample due to their association with phenolic content and antioxidant activity. The sample treated with (7%) extract concentration had a TBARS value of (0.24mg MDA/Kg), while the control sample had a value of (0.99mg MDA/Kg) at the end of  storage period. On the other hand, the meat showed during refrigerated storage an increase in the pH in the control sample (from 5.95 to 6.65), but this increase was less in the treated samples, as it increased from (4.9) to (6), and the same was true for the percentage of free fatty acids. Treatment with the extract led to a decrease in the percentage of free fatty acids by an improvement rate of (40.44%) and a decrease in the total bacteria count when treated with the ethanolic extract. This decrease was proportional to the increase in the concentration of the extract, as the control sample spoiled on the (8)th day of storage, while the sample treated with the (7%) extract remained valid until the (16)th day of storage. The absence of pathogenic E. coli and Staphylococcus aureus was also observed in all treated samples. The study concluded that  treating chicken breast with the etanolic extract of nettle leaves at the a concentration of (7%) was the best way to obtain good anti-lipid peroxidation activity and good anti-microbial growth activity during refrigerated storage at (4±1°C) for (16 days).