Antioxidant effect of essential oils of rosemary, clove and cinnamon on hazelnut and poppy oils Mehmet Musa Özcan ⇑ , Derya Arslan Department of Food Engineering, Faculty of Agriculture, Selcuk University, 42031 Konya, Turkey article info Article history: Received 26 September 2009 Received in revised form 4 October 2010 Accepted 1 January 2011 Available online 22 January 2011 Keywords: Antioxidant effect Spice Essential oil Hazelnut oil Poppy oil abstract Antioxidant effects of essential oils from rosemary (Rosmarinus officinalis), clove (Syzygium aromaticum) and cinnamon (Cinnamomum zeylanicum) were determined on hazelnut and poppy oils. These essential oils were added to the oils at concentrations of 0.25% and 0.5%. Butylated hydroxyanisole (BHA) at 0.02% level served as standard besides the control groups for comparison. The samples were stored 50 °C in darkness for 14 days. The antioxidant activity of the essential oils was determined by measuring peroxide values (meq O 2 /kg oil) at regular intervals. On the basis of peroxide value assay, the essential oils showed stronger antioxidant effect when compared to control groups. BHA was more effective than the essential oils, whilst it exhibited no antioxidative effect on the first few days of storage. Amongst the investigated essential oils, the cinnamon oil was the most effective on retarding lipid oxidation of crude oils, which was followed by clove and rosemary oils. Ó 2011 Published by Elsevier Ltd. 1. Introduction Antioxidants commonly used in food products today are butyl- ated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). In recent years the safety of synthetic food additives, including the possible toxicity of these chemicals used as antioxidants has re- ceived increasing attention. So, there is need for other components to act as antioxidants and to render food products safer for man- kind (Branen, 1975; Kahl & Kappus, 1993). As it is known, mainly the edible oils, fats and fatty foods can undergo deterioration in the course of the time depending on external factors such as heat, light, enzyme and trace metals. As a result of autoxidation espe- cially which occurs with the effect of oxygen in the air, unpleasant taste and smell that are known as the signs of rancidity in oil occur. Autoxidation is an irreversible reaction which goes on spontane- ously when it begins, and its rate is directly related to the oil’s unsaturation degree. The breakdown products formed after oxida- tion process such as peroxides, aldehydes and ketones shorten the shelf life of oils and turn products unacceptable for consumption (Akgül, 1989; Shahidi & Nazck, 1995). As a conclusion of these researches, in order to overcome the stability problems of oils and fats synthetic antioxidants, most of which have phenolic characteristic, such as BHA, BHT, ter-butyl hydroquinone (TBHQ) and gallates have been used as food addi- tives for many years (Akgül, 1989; De Man, 1980). But recent re- ports reveal that these compounds may be implicated in many health risks (Özcan & Akgül, 1995). For example, BHT causes liver expansion (Akgül, 1989). Also, it is well known that these com- pounds cause unpleasant taste and smells as they easily vaporise and degrade (Akgül, 1989; Özcan & Akgül, 1995). To prevent these harmful effects of synthetic antioxidants, the use of antioxidants which are found in foods and various natural materials is recom- mended (Özcan & Akgül, 1995). Researches on rosemary show that compounds which have antioxidant characteristic have phenol character and flavonoids occupy an important part in them (Deck- er, 1997). On the other hand, it was reported that eugenol which is found in clove and cinnamon essential oils is an effective antioxi- dant compound in the researches (Farag, Badei, Hewedi, & El- Baroty, 1989a). It is doubtless, this effect is the result of eugenol’s phenolic structure (Weidenbörner, Hindrof, & Tsotsonos, 1990). The antioxidative effects of natural antioxidants on lipids were studied in recent years as a popular research area. Some of the effective factors on the antioxidative mechanism of natural com- pounds on lipids were expressed as the emulsion type of the sys- tem (Frankel, Huang, & Aeschbach, 1997; Hopia, Huang, Schwarz, German, & Frankel 1996), antagonistic and synergistic effects (Medina, Tombo, Satuè-Gracia, German, & Frankel, 2002; Özcan, 1999; Özcan, 2000), temperature (Sature, Huang, & Frankel, 1995), concentration, hydrophilic or the lipophilic tendency of the system (Frankel, Huang, Aeschbach, & Prior, 1996; Schwarz et al., 2000) and the number and the place of connection of the hy- droxyl groups in aromatic cycle (Chen, Chan, Ho, Fung, & Wang, 1996; Das & Pereira, 1990). Overall strongest activity of rosemary was not surprising be- cause of various findings reported on its stabilising effect (Chang, 0308-8146/$ - see front matter Ó 2011 Published by Elsevier Ltd. doi:10.1016/j.foodchem.2011.01.055 ⇑ Corresponding author. Tel.: +90 332 2232933; fax: +90 332 2410108. E-mail address: mozcan@selcuk.edu.tr (M.M. Özcan). Food Chemistry 129 (2011) 171–174 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem