The greening reaction of skipjack tuna (Katsuwonus pelamis) metmyoglobin promoted by free cysteine during thermal treatment.
PeerJ
; 10: e13923, 2022.
Article
em En
| MEDLINE
| ID: mdl-35996665
ABSTRACT
Background:
Tuna muscle greening is a problem that occurs after heating. A hypothesis has been postulated to address this problem, involving a conserved Cys residue at position 10 (Cys-10) present on tuna myoglobin (Mb) that is exposed during the thermic treatment, forming a disulfide bond with free cysteine (Cys) in the presence of trimethylamine oxide (TMAO), resulting in the greening of the tuna Mb.Methods:
We present a study using skipjack tuna (Katsuwonus pelamis) metmyoglobin (MbFe(III)-H2O) where the effect of free Cys (1-6 mM), TMAO (1.33 mM), and catalase on the greening reaction (GR) was monitored by UV-vis spectrometry during thermal treatment at 60 °C for 30 min. Moreover, the participation of Cys-10 on the GR was evaluated after its blocking with N-ethymaleimide.Results:
The GR occurred in tuna MbFe(III)-H2O after heat treatment with free Cys, forming sulfmyoglobin (MbFe(II)-S) as the responsible pigment for the tuna greening. However, the rate constants of MbFe(II)-S production depended on Cys concentration (up to 4 mM) and occurred regardless of the TMAO presence. We postulate that two consecutive reactions involve an intermediate ferrylmyoglobin (promoted by H2O2) species with a subsequent MbFe(II)-S formation since the presence of catalase fosters the reduction of the rate reaction. Moreover, GR occurred even with blocked Cys-10 residues in tuna Mb and horse Mb (without Cys in its sequence).Discussion:
We found that GR is not exclusive to tuna Mb´s, and it can be promoted in other muscle systems. Moreover, Cys and thermal treatment are indispensable for promoting this pigmentation anomaly.Palavras-chave
Texto completo:
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cisteína
/
Metamioglobina
Limite:
Animals
Idioma:
En
Revista:
PeerJ
Ano de publicação:
2022
Tipo de documento:
Article