Proximate Composition, Microbiological Quality and Sensory Attributes of Mahi-mahi (Coryphaena hippurus) and Emperor Sea Bream (Lethrinus spp.) Fillets Sold on Retail Market
Abstract
Introduction: The variety of seafood on the European market has considerably increased in recent years. This study presents data to the main nutritional values and the sensory properties of two exotic fish species, mahi-mahi (Coryphaena hippurus) and emperor sea bream (Lethrinus spp.), sold on retail market in Germany. Information on the quality of frozen and glazed fillets is still missing, but is important to characterize these products. This also includes details on the substances added to increase the water-binding ability. Aims: The paper aims to assess the quality of exotic fish fillets sold on the German market, through the evaluation of physical and chemical parameters, microbiological quality and sensory attributes. Materials and methods: 10 samples of each fish species were analysed after homogenisation to determine the following parameters: pH-value (with a pH meter); water (gravimetrically); ash (in a muffle furnace at 550 °C); salt (NaCl; by auto-titration); fat (by a modified Smedes method); protein (with a LECO TruSpecN based on the principles of the Dumas combustion method); total phosphorus content (photometrically); total volatile basic nitrogen (TVB-N, using the EU reference method); total viable bacteria count (TVC) and specific fish spoiling bacteria (SSO) (by decimal dilutions method). The sensory assessments were done with cooked and fried fillets by a panel consisting of 6 specialists, using a descriptive method. Results: Lipid, ash and salt contents of mahi-mahi were comparable to the emperor sea bream values. Due to low lipid content, both species can be classified as lean species. The protein amount of emperor sea bream was significantly higher compared to mahi-mahi and many other common fish species. In mahi-mahi samples, slightly higher values of total phosphates content were found. The pH values of emperor sea bream were in a normal range for fresh fish, whereas in mahi-mahi significantly higher values were determined which was not correlated with quality deteriorations. TVB-N values in all investigated samples were low and indicate a sufficient fish freshness of the used raw material. The TVC of different mahi-mahi and emperor sea bream fillets indicated a good to sufficient microbiological status. Conclusion: Pleasant sensory properties, low microbiological charge and low fat contents of emperor sea bream and mahi-mahi lead to the conclusion that these exotic fish products are a valuable enrichment of fish products on the market.
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