TAFT 2015- 5th Trans-Atlantic Fisheries Technology conference (45th WEFTA meeting), Nantes, France, 12 - 15 October 2015, pp.1
Biogenic amines are important as agents of food intoxication and indicators of fish spoilage. Biogenic amine formation can be controlled by inhibiting microbial growth or inhibiting the decarboxylase activity of microbes. Nanoemulsions are regarded as self-preserving antimicrobials since the water present in them is effectively bound by its structure and access to the water by microorganisms is restricted. Nanoemulsions have adverse effects on the structure and function on bacteria by destabilizing the organism’s lipid envelope. Therefore, the aim of this work is to investigate the effects of oil-in-water nanoemulsions using different commercial oils (sunflower, canola, corn, olive, soybean, and hazelnut oils) on the biogenic amine contents of sea bass (Dicentrarchus labrax) fillets stored at 2±2 oC. This project was supported by Scientific and Technological Research Council of Turkey (TÜBİTAK) (TOVAG-113O379). Nanoemulsions were prepared according to the method of Hamouda et al. (1999). Physical properties of nanoemulsions were analyzed in terms of viscosity, particle size of droplets, thermodynamic stability, refractive index, and surface tension. Sea bass were obtained from a local fish farm in İzmir, Turkey. Fish were killed by dipping in ice-cold water (hypothermia) and transported to the laboratory in ice within 24 to 25 h from harvesting. They were immediately gutted and divided into seven lots. One lot was stored on plates wrapped with permeable stretch film. The other samples were treated with nanoemulsions. All samples were stored at 2±2 °C. Biogenic amines were analyzed using a HPLC method (Ozogul et al., 2002). Benzoyl chloride as a derivatization reagent was used and the derivatization procedure was based on that of Redmond and Tseng (1979). In this study, histamine was not detected in any sample analyzed until 10 days of storage. As storage time progressed, putresine, cadaverine, spermidine and spermine, seratonine, tyramine, dopamine and agmatine became the dominant amines. The levels of biogenic amines fluctuated during the storage period. Generally, biogenic amine accumulation in the control is higher than the treated samples. There are many factors affecting the formation of biogenic amines such as aquaculture conditions, food, fish species, body composition, and storage and processing conditions and the presence of decarboxylase-active microorganisms and the availability of free amino acids. The use of nanoemulsions regardless of oil type was found to be effective in inhibiting bacterial growth, hence reducing the biogenic amine formation.