Journal of Food Quality and Hazards Control 2 (2015) 128-133 Journal website: http://www.jfqhc.com Effect of Traditional Marinating on Bacterial and Chemical Characteristics in Frozen Rainbow Trout Fillet S. Maktabi 1* , M. Zarei 1 , M. Chadorbaf 2 1. Department of Food Hygiene, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran 2. Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Abstract Background: In recent years, there has been an increasing interest in using food addi- tives from natural sources to improve taste and also extend shelf life of semi-preserved food. The aim of this paper was to examine chemical and microbiological changes pro- moted by a traditional marinating process in rainbow trout fillets during frozen storage. Methods: Fish fillets were immersed in traditional marinades and stored at -18 ° C for 56 days. Some chemical and microbial characteristics like total volatile basic nitrogen (TVN), thiobarbituric acid (TBA), water holding capacity (WHC), pH, mesophilic, and psychrophilic bacterial count were performed with 7 days interval. The results were analyzed by repeated measure ANOVA test using SPSS v. 16.0 software. Results: Data showed that although the value of TVN, TBA and, WHC in marinated samples were higher than control ones, but the differences were not significant (p>0.05). The numbers of bacteria in marinated samples were lower than control groups and for psychrophilic bacteria was significant (p<0.05). Conclusion: The most obvious finding to emerge from this study is that rainbow trout flesh could be marinated and stored at -18 ˚ C for at least 56 days with no major unfavor- able changes. Introduction The rainbow trout (Oncorhynchus mykiss) is one of the most widely introduced fishes on a global basis. This fish has the ability to culture in most parts of Iran and has been one of the most desirable farmed fish in the last two decades (FAO, 2010; Iranian Fisheries Organization, 2009). Rainbow trout is very closely related to salmon which having the highest content of polyunsaturated fatty acids such as eicosapentaenoic acid and decosahexaenoic acid compared to other fish and seafood (Cunnane and Griffin, 2009). Fatty fish such as rainbow trout has limited shelf life and quality deterioration of this species is mainly caused by rapid growth of microorganisms and * Corresponding author E-mail: s.maktabi@scu.ac.ir lipid oxidation (Gram et al., 1990). So, the off-odor and off-taste of the products affect the consumer acceptability (Moini et al., 2009; Rostamzad et al., 2010). Today, the addition of synthetic preservatives, antioxidants, colorants to extend shelf life has been revised by authori- ties due to certain health problems. Use of natural preservative has been the subject of many investigations (Ahmadi et al., 2014; Attouchi and Sadok, 2012; Halliwell et al., 1995; Nirmal and Benjakul, 2012). Marinades are the solutions, including sugar, spices, oil and vinegar or fruit juice that already has been used to improve the tenderness, juiciness, flavor and aroma (Cadun et al., 2008). Marinating process slows down the Article type Original article Keywords Analysis Food Quality Frozen Foods Trout Received: 23 Jun 2015 Revised: 13 Aug 2015 Accepted: 4 Oct 2015 Downloaded from jfqhc.ssu.ac.ir at 2:43 +0330 on Monday November 29th 2021