Effect of modified atmosphere packaging with freeze-chilling on some quality parameters of raw whiting, mackerel and salmon portions

摘要

Modified atmosphere packaging (MAP) was combined with freeze-chilling to extend the shelf-life of raw whiting, mackerel and salmon fillets/portions. The MAP packs for mackerel and salmon (60% N_2/40% CO_2), and for whiting (30% N_2/40% CO_2/ 30% O_2)maintained their shape during freeze-chilling whereas packs with 100% CO_2 were slightly imploded with concave sides. The chosen chilled shelf-life of 5-7 days in the MAP trials was vindicated by the results as the products were near the end of their shelf-life (in acceptability terms) after 5 (whiting and mackerel) and 7 (salmon) days. This compares with shelf lives of 3 days and 5 days, respectively, for freeze-chilled fillets in air. Samples in MAP had lower total viable counts than samples in air for raw fillets/portions of each of the three species. However, MAP did not influence odour or acceptability scores, but had a variable effect (generally small) on fillet colour, springiness, drip loss, total volatile base nitrogen/trimethylamine content,peroxide values and free fatty acid contents. Industrial relevance: raw fish is highly perishable and has a short shelf-life. The results of these tests showed that raw whiting, mackerel and salmon portions/fillets performed well as freeze-chilled MAP products and that these combined technologies confer logistic benefits in product distribution and retailing.