Assessment of Commercial Quality Evaluation of Yellowfin Tuna Thunnus albacares Meat Based on Myoglobin Properties

Abstract

Four quality grades (excellent, good, acceptable, and "not acceptable") of yellowfin tuna meat (Thunnus albacares), as judged by a professional appraiser, were compared based on the red/ox state and extractability of myoglobin (Mb). As a result, the metMb ratio of the "not acceptable" grade of meat was significantly higher than that of the other higher-grade samples. In contrast, the highest ratio of oxyMb was found in the "excellent" meat, followed by good > acceptable > "not acceptable" meats. Color measurement revealed significant differences in a* value between the different grades of meat, but showed essentially no difference in L* and b* values. Both a* value and redness index (a*/b*) showed high correlation coefficients with metMb ratio. Mb extractability tended to be higher in the higher grade of meat. In conclusion, the commercial appraisal of tuna meat quality was demonstrated to be reliable. Keywords: tuna, meat, quality, color, myoglobin *To whom correspondence should be addressed. E-mail: aochiai@tokai-u.jp IntroductionSeven species of tunas are consumed around the world. Yellowfin tuna (Thunnus albacores), whose meat is characterized by a light red color and less fat, is one of the most commercially important and favored tuna species. This scombridae species inhabits tropical and subtropical waters around the world. Therefore, this species is generally exported to Japan from tropical countries, such as Indonesia, Taiwan, and so on (MMAF, 2012). A quality check is frequently performed before processing and transportation. Sensory analyses performed by experienced appraisers are generally carried out to determine freshness as a composite of qualitative traits. Color is one of the most important factors affecting consumer preferences. The meat color of tuna is closely related with myoglobin (Mb) content and the red/ox state of the heme iron.Mb is a small globular protein whose biological function is basically to temporarily store oxygen in skeletal and cardiac muscles for facilitation of respiration (Livingston et al., 1983), though new functions of Mb have been recently reported, such as nitrogen oxide scavenging activity (Cossins and Berenbrink, 2008;Flögel et al., 2010;Helbo et al., 2012). Generally, Mb content changes dependent on animal species, muscle part, age, and diet of the animal. Pale colored meat, such as chicken and pork, generally contain lower concentrations of Mb compared with red colored meat such as beef. Oxidative muscles, namely, slow skeletal muscle (including the dark muscle of fish) and heart muscle, contain abundant Mb. In scombridae fish such as tuna, abundant Mb is also found in fast skeletal muscle (also referred to as ordinary muscle, light muscle or white muscle).An iron atom of heme is placed in the hydrophobic region of Mb, binding the imidazole group of proximal histidine directly and distal histidine through a coordinate bond (Phillips and Schoenboen, 1981). The binding of oxygen, as well as the state of an iron atom in the heme pocket, contributes to the meat colo...

Characterization and Antioxidant Activity of Collagen, Gelatin, and the Derived Peptides from Yellowfin Tuna (Thunnus albacares) Skin

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Quality of Cultured Wader Pari During Storage at Different Temperature

“…Kesegaran ikan tuna biasanya diukur dari profil protein myoglobinnya. Nurilmala et al (2013) melaporkan karakterisasi myoglobin dapat dilakukan dalam penentuan kesegaran ikan tuna. Produk-produk tuna tersebut menghasilkan limbah berupa tulang dan kulit.…”

Detection of Histamine-Producing Bacteria on Tuna Species using Histidine Decarboxylase (hdc) and 16S rRNA

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