Effects of Hydroalcoholic and Water Extracts of Nettle Leaf (Urtica dioica L.) on Chemical Properties of Superchilled Minced Meat of Common Kilka (Clupeonella cultriventris caspia)

Background: Antioxidant activities of plant extracts are being studied to increase the shelf life of fish products. Some plants such as Urtica dioica L. (nettle) can be a good source of antioxidants. The objective of this study was to evaluate the effects of hydroalcoholic and water extracts of nettle leaf on the chemical properties of superchilled minced meat of the common kilka fish (Clupeonella cultriventris caspia). Methods: One hundred g of minced meat of kilka was mixed with 200 and 400 ppm of both hydroalcoholic and water extracts of nettle separately, and stored at -2 °C. The Total Volatile Basic Nitrogen (TVB-N) and Thiobarbituric Acid Reactive Substances (TBARS) of the samples were analyzed at days 0, 3, 7, 14, 21 and 28. The statistical analysis was carried out using Duncan’s multiple range tests in MStat-C software. Results: Both hydroalcoholic and water extracts of nettle extended the shelf life of minced kilka from 2 days to 8 days. However, no relation (p>0.05) was observed between chemical values and kind of extracts. Also, there was no significant difference (p>0.05) between two concentration levels of extracts and chemical values. Conclusion: Treatment levels of nettle extracts could effectively delay chemical deterioration, and extend the shelf life of minced kilka during storage. A combination of superchilling temperature (-2 °C) and treatment of minced kilka with 200 and 400 ppm of hydroalcoholic and water extracts of nettle can extend the shelf life to 28 days. Based on the results of this study, it is proposed that these plant extracts can be used as safe preservatives for minced fish.