Eumelanin Detection in Melanized Focal Changes but Not in Red Focal Changes on Atlantic Salmon ( Salmo salar ) Fillets
Superficial discolored spots on Atlantic salmon ( Salmo salar ) fillets are a serious quality problem for commercial seafood farming. Previous reports have proposed that the black spots (called melanized focal changes (MFCs)) may be melanin, but no convincing evidence has been reported. In this stud...
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ftdoajarticles:oai:doaj.org/article:026b83c7fba64d6884851c10cd4d57ac 2024-01-07T09:42:12+01:00 Eumelanin Detection in Melanized Focal Changes but Not in Red Focal Changes on Atlantic Salmon ( Salmo salar ) Fillets Kazumasa Wakamatsu Johannes M. Dijkstra Turid Mørkøre Shosuke Ito 2023-11-01T00:00:00Z https://doi.org/10.3390/ijms242316797 https://doaj.org/article/026b83c7fba64d6884851c10cd4d57ac EN eng MDPI AG https://www.mdpi.com/1422-0067/24/23/16797 https://doaj.org/toc/1661-6596 https://doaj.org/toc/1422-0067 doi:10.3390/ijms242316797 1422-0067 1661-6596 https://doaj.org/article/026b83c7fba64d6884851c10cd4d57ac International Journal of Molecular Sciences, Vol 24, Iss 23, p 16797 (2023) Atlantic salmon melanized focal changes red focal changes eumelanin pheomelanin PTCA Biology (General) QH301-705.5 Chemistry QD1-999 article 2023 ftdoajarticles https://doi.org/10.3390/ijms242316797 2023-12-10T01:36:44Z Superficial discolored spots on Atlantic salmon ( Salmo salar ) fillets are a serious quality problem for commercial seafood farming. Previous reports have proposed that the black spots (called melanized focal changes (MFCs)) may be melanin, but no convincing evidence has been reported. In this study, we performed chemical characterization of MFCs and of red pigment (called red focal changes (RFCs)) from salmon fillets using alkaline hydrogen peroxide oxidation and hydroiodic acid hydrolysis. This revealed that the MFCs contain 3,4-dihydroxyphenylalanine (DOPA)-derived eumelanin, whereas the RFCs contain only trace amounts of eumelanin. Therefore, it is probable that the black color of the MFCs can be explained by the presence of eumelanin from accumulated melanomacrophages. For the red pigment, we could not find a significant signature of either eumelanin or pheomelanin; the red color is probably predominantly hemorrhagic in nature. However, we found that the level of pigmentation in RFCs increased together with some melanogenic metabolites. Comparison with a “mimicking experiment”, in which a mixture of a salmon homogenate + DOPA was oxidized with tyrosinase, suggested that the RFCs include conjugations of DOPAquinone and/or DOPAchrome with salmon muscle tissue proteins. In short, the results suggest that melanogenic metabolites in MFCs and RFCs derive from different chemical pathways, which would agree with the two different colorations deriving from distinct cellular origins, namely melanomacrophages and red blood cells, respectively. Article in Journal/Newspaper Atlantic salmon Salmo salar Directory of Open Access Journals: DOAJ Articles International Journal of Molecular Sciences 24 23 16797 |
institution |
Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Atlantic salmon melanized focal changes red focal changes eumelanin pheomelanin PTCA Biology (General) QH301-705.5 Chemistry QD1-999 |
spellingShingle |
Atlantic salmon melanized focal changes red focal changes eumelanin pheomelanin PTCA Biology (General) QH301-705.5 Chemistry QD1-999 Kazumasa Wakamatsu Johannes M. Dijkstra Turid Mørkøre Shosuke Ito Eumelanin Detection in Melanized Focal Changes but Not in Red Focal Changes on Atlantic Salmon ( Salmo salar ) Fillets |
topic_facet |
Atlantic salmon melanized focal changes red focal changes eumelanin pheomelanin PTCA Biology (General) QH301-705.5 Chemistry QD1-999 |
description |
Superficial discolored spots on Atlantic salmon ( Salmo salar ) fillets are a serious quality problem for commercial seafood farming. Previous reports have proposed that the black spots (called melanized focal changes (MFCs)) may be melanin, but no convincing evidence has been reported. In this study, we performed chemical characterization of MFCs and of red pigment (called red focal changes (RFCs)) from salmon fillets using alkaline hydrogen peroxide oxidation and hydroiodic acid hydrolysis. This revealed that the MFCs contain 3,4-dihydroxyphenylalanine (DOPA)-derived eumelanin, whereas the RFCs contain only trace amounts of eumelanin. Therefore, it is probable that the black color of the MFCs can be explained by the presence of eumelanin from accumulated melanomacrophages. For the red pigment, we could not find a significant signature of either eumelanin or pheomelanin; the red color is probably predominantly hemorrhagic in nature. However, we found that the level of pigmentation in RFCs increased together with some melanogenic metabolites. Comparison with a “mimicking experiment”, in which a mixture of a salmon homogenate + DOPA was oxidized with tyrosinase, suggested that the RFCs include conjugations of DOPAquinone and/or DOPAchrome with salmon muscle tissue proteins. In short, the results suggest that melanogenic metabolites in MFCs and RFCs derive from different chemical pathways, which would agree with the two different colorations deriving from distinct cellular origins, namely melanomacrophages and red blood cells, respectively. |
format |
Article in Journal/Newspaper |
author |
Kazumasa Wakamatsu Johannes M. Dijkstra Turid Mørkøre Shosuke Ito |
author_facet |
Kazumasa Wakamatsu Johannes M. Dijkstra Turid Mørkøre Shosuke Ito |
author_sort |
Kazumasa Wakamatsu |
title |
Eumelanin Detection in Melanized Focal Changes but Not in Red Focal Changes on Atlantic Salmon ( Salmo salar ) Fillets |
title_short |
Eumelanin Detection in Melanized Focal Changes but Not in Red Focal Changes on Atlantic Salmon ( Salmo salar ) Fillets |
title_full |
Eumelanin Detection in Melanized Focal Changes but Not in Red Focal Changes on Atlantic Salmon ( Salmo salar ) Fillets |
title_fullStr |
Eumelanin Detection in Melanized Focal Changes but Not in Red Focal Changes on Atlantic Salmon ( Salmo salar ) Fillets |
title_full_unstemmed |
Eumelanin Detection in Melanized Focal Changes but Not in Red Focal Changes on Atlantic Salmon ( Salmo salar ) Fillets |
title_sort |
eumelanin detection in melanized focal changes but not in red focal changes on atlantic salmon ( salmo salar ) fillets |
publisher |
MDPI AG |
publishDate |
2023 |
url |
https://doi.org/10.3390/ijms242316797 https://doaj.org/article/026b83c7fba64d6884851c10cd4d57ac |
genre |
Atlantic salmon Salmo salar |
genre_facet |
Atlantic salmon Salmo salar |
op_source |
International Journal of Molecular Sciences, Vol 24, Iss 23, p 16797 (2023) |
op_relation |
https://www.mdpi.com/1422-0067/24/23/16797 https://doaj.org/toc/1661-6596 https://doaj.org/toc/1422-0067 doi:10.3390/ijms242316797 1422-0067 1661-6596 https://doaj.org/article/026b83c7fba64d6884851c10cd4d57ac |
op_doi |
https://doi.org/10.3390/ijms242316797 |
container_title |
International Journal of Molecular Sciences |
container_volume |
24 |
container_issue |
23 |
container_start_page |
16797 |
_version_ |
1787423136515358720 |