The Effect of Ethanol Extracts from Nettle, Rosemary and Myrtle Leaves on Lipid Oxidation and Microbial Growth of Kavurma during Refrigerated Storage

Abstract

Kavurma is a cooked meat product which is produced in Turkey, the Middle East and some Asia countries. In this study, the effect of ethanol extracts from nettle, rosemary and myrtle leaves on lipid oxidation and microbial growth of vacuum-packaged kavurma was investigated. Kavurma was made from beef meat and beef meat fat in 4 groups: No-added extract, 0.4% nettle extract, 0.4% rosemary extract and 0.4% myrtle extract. The kavurma produced was stored at 4℃ for 180 days. The ethanol extracts from nettle, rosemary and myrtle slowed down the lipid oxidation and inhibited the bacterial growth of kavurma. The best results were found in the treatment with myrtle extract for lipid oxidation, and in the treatment with nettle extract for microbial growth. Treatment had no significant effect on fatty acid profiles. These results suggest that the use of myrtle and nettle extracts could control lipid oxidation and microbial growth in kavurma, respectively.Keywords: kavurma, nettle, rosemary, myrtle, lipid oxidation, microbial growth *To whom correspondence should be addressed. E-mail: sturhan@omu.edu.tr IntroductionKavurma is a cooked meat product which is mainly produced in Turkey, the Middle East and some Asia countries (Gokalp et al., 2002). In traditional processing, it is produced from beef or mutton meat, beef fat and salt. The meats are diced (approximately 4 × 5 cm) and mixed with salt, and then cooked in animal fat using a double sided steam cauldron (Gokalp et al., 2002; Aksu and Kaya, 2005;Cetin et al., 2005;Aksu, 2007). In the modern plants, antimicrobials, antioxidants, nitrite, nitrate, spices (e.g. black pepper and thyme) and other ingredients such as nuts may be added to this mixture (Gokalp et al., 2002; Bozkurt and Belibagli, 2009). After cooking, it is filled into natural or artificial casings while warm and stored under anaerobic conditions. Recently, it has also become commercially available in sliced, vacuum-packaged forms produced in modern plants (Cetin et al., 2005;Aksu, 2007; Aksu, 2009).Due to the high animal fat content, open-kettle cooking and microbial contamination after cooking, kavurma is prone to spoilage by both lipid oxidation and microbial action. In addition, with cooking meats are even more vulnerable to oxidation, since antioxidative enzymes in the muscle, like catalase and superoxidase dismutase, may denature and lose their activity, while iron-containing proteins at the same time become a source of catalytic iron or, like myoglobin and hemoglobin, may be transformed into partly denaturated forms with peroxidase activity (Aksu and Kaya, 2005). The oxidation process greatly reduces the nutritional value of lipids and leads to the development of undesirable rancidity and potentially toxic reaction products (Tang et al., 2001), whereas microbial growth may cause both spoilage and foodborne diseases (Cetin et al., 2005;Fernandez-Lopez et al., 2005;Georgantelis et al., 2007). Therefore, the preventing or retardation of the oxidation process and bacterial growth in cooked meats are factor...

Volatile profile and fatty acid composition of kavurma (a cooked uncured meat product) produced with animal fat combinations

“…[3] In the production of kavurma, meat obtained from carcasses of beef or sheep after the cutting into small pieces are fried in open or closed cauldrons in animal fats. [4,5] After the cooking process, meat is filled into natural or artificial casing and the fat used while cooking is added over it in a way to fill in the gaps between meat and to cover the surface. [3] In this way, an anaerobic environment is partially created.…”