نعناع (mentha spicata l

Today, the tendency has increased to the use of bio-preservatives, including plant extracts, as an alternative to synthetic antioxidants and antimicrobials. On the other hand, the addition of lipids, such as oleic acid to biopolymers in active packaging reduces their permeability to water vapor. To investigate the antioxidant and antimicrobial effect of Mentha spicataL. extract in bio-composite carboxymethyl cellulose-based coating on the shelf life of common carp fillets in cold conditions, an experiment was conducted in a completely randomized design with six treatments including carboxymethyl cellulose coating (CMS, 2.5%), CMS combined with oleic acid (OA, 1.5%), CMS combined with OA and enriched with 0.5, 1, 1.5 and 2% Mentha spicataextract, and three replications for 9 days. The results showed that OA improved the protective effect of CMS. The use of Mentha spicata extract in the bio-composite coating, especially at the highest concentrations, significantly (p < /em> <0.05) reduced the number of psychrotrophic bacteria, the index of thiobarbituric acid, free fatty acids, total volatile nitrogen compounds, and pH of common carp fillets during cold storage. The antioxidant and antimicrobial effect of Mentha spicataextract was dose-dependent. Therefore, Mentha spicata extract, with its antioxidant and antimicrobial properties in combination with the composite coating of CMS-OA, can be used as a bio-preservative in active packaging, to maintain quality and increase the shelf life of fish fillets during short-term storage in refrigeration.

Water scarcity adversely affects many physiological and metabolic processes of the plants. To study the effects of drought stress and fertilization on some physiological characteristics, essential oil percentage and yield of spearmint, a field experiment was conducted at the Research Farm of the College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. The experiment was conducted in a split plot arrangement based on a randomized complete block design with three replications. Treatments included three irrigation treatments (100%, 75% and 50% of plant water requirement) as the main plot and four fertilizer regimes including no fertilizer (control), chemical fertilizer (N), bio-fertilizer (rhizome inoculation with Azotobacter, Pseudomonas and mycorrhiza) and integration of biological fertilizer and 50% chemical fertilizer as the sub-plot. The results showed that all traits measured were significantly affected by the main and interaction effects of deficit irrigation and fertilizer. The content of chlorophyll a, chlorophyll b, carotenoids, total chlorophyll, percentage and yield of essential oil and yield decreased with increasing water stress while the rate of carbohydrate and proline as well as the electrolyte leakage percentage increased. Furthermore, the results showed that under 100% and 75% irrigation systems, application of chemical and integrated fertilizers improved the physiological characteristics, yield and percentage and yield of essential oil. Under 50% irrigation regime, the best performance was related to bio fertilizer.