Resumen

FARIAS VERA, Carmen María; NUNEZ, Atilano  y  MENDEZ, Jesús. Effect of the modified atmosphere packaging on the physicochemical characteristics of fillets of bagre lau lau (brachyplatystoma vaillanti) during the storage. Saber [online]. 2013, vol.25, n.3, pp.294-301. ISSN 1315-0162.

The physicochemical characteristics of fillets of bagre Lau lau (Brachyplatystoma vaillanti) were evaluated. The fillets were packed in modified atmosphere (A₁ = 100 % Air; A₂ = 25 % CO₂:75 % N₂; A₃ = 50 % CO₂:50 % N₂; A₄ = 75 % CO₂:25 % N₂) and then stored at 2 ºC ± 1 during 28 days. Indicators of physical deterioration (pH, instrumental texture) and chemical (total volatile bases), at different times of storage (0, 3, 7, 10, 14, 17, 21, 24 and 28 days) were analyzed. The fillets showed average initial values of pH: 6,42, hardness: 42,941 N/mm, TVB: 23,503 mg N/100g, maintaining the ideal conditions of freshness for its storage. In the MAP 1, there was production of CO₂ and reduction of the O₂ up to zero, which was totally consumed by the microorganisms and by the post-mortem metabolic activity of the muscle. For the atmosphere containing different concentrations of CO₂ there was linear decrease in the concentration of CO₂ during the storage, with the formation of carbonic acid which as a consequence was a factor in the conservation of the product. There were no relation between the pH values and time of storage but there was with the atmosphere, being the lowest pH for the fillets at the MAP 4 with the highest concentration of CO2, where it appeared to be the best effect for keeping the quality of the fillets. The hardness (resistance to the cut) was not related to the time of storage or to the MAP. The formation TVB did not gave exact information about the quality or freshness of the fillets, the levels increased only in the latest two times when the signs of deterioration were evident. The shelf life of the fillets were of 7 days for the MAP 1 (A₁ = 100 % Air), whereas for the packed ones under different concentrations of CO₂ there were 21 days for the MAP 2 and 3 (A₂ = 25 % CO₂:75 % N₂; A₃ = 50 % CO₂:50 % N₂) and up to 24 days for the MAP 4 (A₄ = 75 % CO₂: 25 % N₂). Only there existed an inverse highly significant correlation between the concentration of CO₂ and BVT.

Palabras clave : Filetes de pescado; envasado en atmósfera modificada; características físico-químicas; vida útil; Fish fillets; modified atmosphere packaging; physicochemical characteristics shelf life.

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