Improvement of the commercial quality of chilled Norway lobster ( Nephrops norvegicus) stored in slurry ice: Effects of a preliminary treatment with an antimelanosic agent on enzymatic browning

• Published in: Food chemistry 2007, Vol.103 (3), p.741-748
• Main Authors: Aubourg, Santiago P., Losada, Vanesa, Prado, Marta, Miranda, José M., Barros-Velázquez, Jorge
• Format: Article
• Language: English
• Subjects: antimelanosic agents; Biological and medical sciences; cold storage; cooling; Enterobacteriaceae; Enzymatic browning; Fish and seafood industries; Food engineering; Food industries; food preservation; food storage; Fundamental and applied biological sciences. Psychology; General aspects; ice; Ice slurries; lobsters; Melanosis; Nephrops norvegicus; Norway lobster; Refrigeration; sensory evaluation; Sensory quality; slurry ice; storage quality
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2006.09.022

The use of slurry ice is gaining increasing importance as an advanced method for the hygienic and efficient chilling and sub-zero storage of aquatic food products. In this work, this technology was applied as a novel technique for the chilling and storage of Norway lobster ( Nephrops norvegicus) – a crustacean species of high-commercial value – under refrigeration conditions at −1.5 °C. In addition, the effects of a preliminary treatment with 0.5% Na HSO 3 on surface browning were evaluated and compared with the results obtained in control batches not subjected to such treatment. The processing of lobster in slurry ice significantly ( p < 0.05) slowed down microbial spoilage, as determined by the counts of aerobes, psychrotrophs, proteolytic bacteria, and lactose-fermenting Enterobacteriaceae, and by the formation of volatile amines. Likewise, the autolytic breakdown mechanisms – as determined by the K value – were also significantly ( p < 0.05) inhibited in the slurry ice batch. Remarkably, preliminary treatment with 0.5% sodium metabisulphite permitted better maintenance of the parameters involved in sensory quality – especially as regards the aspect of the carapace – as compared with non-treated batches, and allowed a shelf life of 9 days without surpassing the 150 mg/kg legal limit established for this food additive. On contrast, the non-treated batch stored in slurry ice exhibited a shelf life of 5 days. The combination of technological treatments proposed in this work – preliminary antimelanosic treatment and storage in slurry ice – may be successfully applied to other fresh and frozen shellfish species with a view to extending shelf life and to avoiding the legal and toxicological problems derived from current abuse of such antimelanosic agents to prevent shellfish browning.