Mahmoud Mohamed A A, Tybussek Thorsten, Loos Helene M, Wagenstaller Maria, Buettner Andrea
Chair of Aroma and Smell Research, Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
Sensory Analytics Department, Fraunhofer Institute for Process Engineering and Packaging IVV, Freising, Germany.
Front Chem. 2018 Jun 25;6:241. doi: 10.3389/fchem.2018.00241. eCollection 2018.
Although the microbiota is considered to be the primary source of off-flavors in farmed fish, there is a lack of information about the possible contribution of feeds to fish malodor. For this reason, the current study was designed to perform comprehensive sensory and chemo-analytical characterization of fish feed constituents that can impact the quality of farmed fish, and to determine whether feeds cause malodor accumulation in fish. To this aim, odorants in four commercial fish feeds were extracted using solvent assisted flavor evaporation (SAFE) and characterized by comparative aroma extract dilution analysis (cAEDA) and multi-dimensional gas chromatography-mass spectrometry/olfactometry (MD-GC-MS/O). The odorants in the fish feed samples were correlated with their respective sensory and fatty acid profiles. The cAEDA studies revealed the presence of 81 odorants of which 55 compounds were common to all the samples. Most of these odorants are identified here for the first time in fish feeds, and include skatole, indole, ()-2,4,7-tridecatrienal, 4-ethyloctanoic acid, and cresols. Additionally, geosmin and 3-isopropyl-2-methoxypyrazine, known for their contribution to fish taint, and other cyanobacterial by-products, dimethyldisulfide and dimethyltrisulfide, were identified in feed samples. The results suggest that fish feed may contribute to fish malodor. Most of these off-flavors were linked to lipid source (fish oil or plant/lard alternatives), unsaturated fatty acids contents, and protein type (plant-based or fishmeal-based sources) in the feed.
尽管微生物群被认为是养殖鱼类产生异味的主要来源，但关于饲料对鱼体异味可能产生的影响却缺乏相关信息。因此，本研究旨在对可能影响养殖鱼类品质的鱼饲料成分进行全面的感官和化学分析表征，并确定饲料是否会导致鱼体异味的积累。为此，采用溶剂辅助风味蒸发（SAFE）法提取了四种商业鱼饲料中的气味物质，并通过比较香气提取物稀释分析（cAEDA）和多维气相色谱 - 质谱联用/嗅闻法（MD - GC - MS/O）对其进行表征。将鱼饲料样品中的气味物质与其各自的感官特征和脂肪酸谱进行关联分析。cAEDA研究表明存在81种气味物质，其中55种化合物在所有样品中都有。这些气味物质中的大多数在此首次在鱼饲料中被鉴定出来，包括粪臭素、吲哚、（）-2,4,7 - 十三碳三烯醛、4 - 乙基辛酸和甲酚。此外，在饲料样品中还鉴定出了对鱼体异味有贡献的土臭素和3 - 异丙基 - 2 - 甲氧基吡嗪，以及其他蓝藻副产物二甲基二硫和二甲基三硫。结果表明鱼饲料可能会导致鱼体产生异味。这些异味大多与饲料中的脂质来源（鱼油或植物/猪油替代品）、不饱和脂肪酸含量以及蛋白质类型（植物性或鱼粉型来源）有关。
