Abstract

Extraction of natural substances with antioxidant activity, to replace synthetic food preservatives has gained great importance. Medicinal plants have traditionally been used in folk medicine as well as to extend the shelf life of foods. Melissa officinalisL., an aromatic Lamiaceae has the main phenolic components that are useful to utilize as antioxidant. In this work, M. officinalis L. leaves was distilled in a Clevenger apparatus to obtain essential oil, chemical components was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Antioxidant activity of essential oil was evaluated by peroxide value, Iodine value and conjugated Dienes. Also the influence of this antioxidant on shelf life of Bezhi bersagh (a local confection in Ilam, Iran) was investigated. As a result, Neral and Beta-Caryophyllene was the most components in chemical analysis of essential oils. Free fatty acid during 1st till 8th week was increased significantly. Peroxide value increased linearly with storage time. Variation of both synthetic and natural antioxidant in aspect of Iodine values was reduces slowly. Conjugated Dienes (CD) changes in oil sample containing essential oil and butylated hydroxy-anisole (BHA) are same approximately. It was clear that shelf life of Bezhi Bersagh can be increased by adding antioxidants.

Key words: Melissa officinalis, antioxidant, GC-MS, peroxide value, iodine value.