The aim of the study was to investigate the effect of pH on the lipid oxidation of red onion skin extracts (ROSEs) treated with washed tilapia muscle model systems (WTMS). Minced and buffered washed samples were prepared at pH and . The WTMS were treated with2 different concentrations of red onion skin prior to storage for 5 days. Lipid oxidation was investigated via peroxide values (PVs), thiobarbituric acid reactive substances (TBARS), and the formation of volatile compounds. Fatty acid profiles of the samples were also identified. The ROSEs were able to significantly suppress the PV (~71%) and TBARS (~42%) formation. | Turkish Journal of Chemistry Turk J Chem 2020 44 1528-1538 http chem TÜBİTAK Research Article doi kim-2004-47 Effect of pH on lipid oxidation of red onion skin extracts treated with washed tilapia Oreochromis niloticus muscle model systems 1 1 2 2 1 Senem GÜNER Yavuz YAĞIZ Zeynal TOPALCENGİZ Hordur G. KRISTINSSON George BAKER 1 4 5 1 Paul SARNOSKI Bruce A. WELT Amarat SIMONNE Maurice R. MARSHALL 1 Food Science and Human Nutrition Department University of Florida Gainesville FL USA 2 Department of Food Engineering Faculty of Engineering and Architecture Muş Alparslan University Muş Turkey 3 Matis ohf. Vinlandsleid Reykjavik Iceland 4 Department of Agricultural and Biological Engineering Institute of Food and Agricultural Sciences University of Florida Gainesville FL USA 5 Institute of Food and Agricultural Sciences University of Florida Gainesville FL USA Received Accepted Published Online Final Version Abstract The aim of the study was to investigate the effect of pH on the lipid oxidation of red onion skin extracts ROSEs treated with washed tilapia muscle model systems WTMS . Minced and buffered washed samples were prepared at pH and . The WTMS were treated with2 different concentrations of red onion skin prior to storage for 5 days. Lipid oxidation was investigated via peroxide values PVs thiobarbituric acid reactive substances TBARS and the formation of volatile compounds. Fatty acid profiles of the samples were also identified. The ROSEs were able to significantly suppress the PV 71 and TBARS 42 formation. Hexanal and octanal formations in the WTMS were relatively less in the ROSE-treated samples. The WTMS samples prepared at pH were more vulnerable to lipid oxidation than those prepared at pH . Red onion skin polyphenols may increase the lag phase of lipid oxidation depending on pH levels resulting in the shelf life extension of raw fish. Key words Onion skin polyphenols .
