The effect of vacuum packaging on physicochemical changes in rainbow trout (Oncorhynchus mykiss) during cold storage
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The aim of the study was to monitor changes in selected physical (aw water activity, pH values) and chemical (TVBN total volatile basic nitrogen, TMA-N trimethylamine nitrogen, FFA free fatty acids, PV peroxide values, TBA thiobarbituric acid value) properties in the shelf life of rainbow trout (Oncorhynchus mykiss) muscle. A total of 192 trout were examined.
Control samples (96 samples) were simply packaged in contact with atmospheric oxygen, while experimental samples (96 samples) were packaged in a commercial vacuum (98%). All the samples were stored at 2 ± 2° C for 11 days. Analyses were performed on storage days 1, 2, 4, 7, 9, and 11. During the experiment, aw values increased in both types of packaging (in air: 0.982; vacuum-packaged: 0.989). At the end of storage, TVBN and TMA concentrations were at 28.88 ± 4.42 and 19.28 ± 3.00 mg·100 g-1, respectively, in the muscle of vacuum-packaged trout; and at 30.52 ± 2.91 and 19.94 ± 2.05 mg·100 g-1, respectively, in fish in simple packaging. The FFA content in vacuum-packaged fish initially declined before increasing to 3.67 ± 2.37% of total fat as oleic acid later in the experiment. The pattern of PV changes was inconclusive, and significant changes were observed in both types of packaging. On monitoring day 11, TBA values had increased to 7.34 ± 3.10 mg·kg-1 in vacuum-packaged fish and to 26.03 ± 8.00 mg·kg-1 in fish in simple packaging. Free fatty acids are not a good indicator of spoilage because they are converted to hydroperoxides. Vacuum packaging effectively slowed down oxidative changes in rainbow trout muscle. The peroxide content is not a suitable indicator of shelf life as peroxides are decomposed to secondary products. Total volatile basic nitrogen and thiobarbituric acid value can be recommended as suitable indicators of freshness and shelf life.
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Podrobná bibliografie
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Hlavní autor
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František Ježek
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Další autoři
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Hana Buchtová, 1959-
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Typ dokumentu
- Články
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Fyzický popis
- Ilustrace
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Publikováno v
- Acta veterinaria. -- ISSN 0001-7213. -- Roč. 83, č. suppl. 10 (2014), s. S51-S58
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Témata
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Popis jednotky
- 5 grafů
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Bibliografie
- Literatura na s. S57-S58
