Chiesa Luca Maria, Pavlovic Radmila, Nobile Maria, Di Cesare Federica, Malandra Renato, Pessina Davide, Panseri Sara
Department of Health, Animal Science and Food Safety, Università Degli Studi di Milano, Via Celoria 10, 20133 Milan, Italy.
ATS Milano-Città Metropolitana, Director of Veterinary Unit, 20122 Milano, Italy.
Foods. 2020 Dec 18;9(12):1896. doi: 10.3390/foods9121896.
This study aims to discriminate fresh fish from frozen/thawed by identification of the key metabolites that are altered during the freezing/thawing processing. Atlantic salmon ( and bullet tuna () were selected as they are representative of broad consumption, and susceptible to pathogen contamination. Atlantic salmon samples were subjected to the following regimes: -20 °C (24h) and -35 °C (15 h) freezing, then thawed respectively in the blast chiller and in the cold room and analyzed immediately or after 10 days; (2) bullet tuna samples were frozen at -18 °C and thawed after 15, 30 and 90 days. High resolution mass spectrometry based on untargeted metabolomic analyses and statistical data treatment confirmed significant variations in the quantity of certain metabolites: the amount of l-phenylalanine in salmon increased immediately after thawing while that of anserine decreased. The concentration of l-arginine and its metabolites was altered at the 10th day after thawing rendering them promising markers of salmon freezing/thawing. As regards bullet tuna, compounds resulting from lipid degradation (l-α-Glyceryl-phosphoryl-choline and N-methyl-ethanolamine phosphate) increased notably during the storage period. This approach could be used to reveal common fraudulent incidents such as deliberate replacement of fresh fish with frozen/thawed, with food safety risks as the primary implication.
本研究旨在通过识别冷冻/解冻过程中发生变化的关键代谢物，区分新鲜鱼和冷冻/解冻鱼。选择大西洋鲑鱼（Salmo salar）和金枪鱼（Thunnus obesus）作为研究对象，因为它们具有广泛的消费代表性，且易受病原体污染。大西洋鲑鱼样本经历以下处理：在-20°C（24小时）和-35°C（15小时）下冷冻，然后分别在冲击式冷却器和冷藏室中解冻，并立即或在10天后进行分析；（2）金枪鱼样本在-18°C下冷冻，并在15、30和90天后解冻。基于非靶向代谢组学分析和统计数据处理的高分辨率质谱法证实了某些代谢物数量的显著变化：鲑鱼解冻后，L-苯丙氨酸的含量立即增加，而鹅肌肽的含量则下降。解冻后第10天，L-精氨酸及其代谢物的浓度发生了变化，使其成为鲑鱼冷冻/解冻的有前景的标志物。至于金枪鱼，脂质降解产生的化合物（L-α-甘油磷酸胆碱和N-甲基乙醇胺磷酸盐）在储存期间显著增加。这种方法可用于揭示常见的欺诈事件，如故意用冷冻/解冻鱼替代新鲜鱼，主要涉及食品安全风险。
