Combination of bulk storage in controlled and modified atmospheres with modified atmosphere packaging system for chilled whole gutted hake

摘要

Whole gutted hake placed in boxes of ice were kept in modified and controlled atmospheres for 12 days with the gas mixture 60%CO2/15%O2/25%N2 (v/v/v) at 2±1°C. Each lot of hake was then subdivided into two other lots and these were packed on trays, some of them in air and some in the same mixture of gases. The trays were kept at 2°C until spoilage. The shelf-life of the hake stored in these conditions was assessed by physical (pH), chemical (TVBN (total volatile basic nitrogen) and TMA-N (trimethylamine nitrogen)) and sensory (inspection and taste panel) analyses. The results of these analyses indicated that the control lot (stored in air throughout) was rejected before the lots kept in adjusted atmospheres. However, the taste panel accepted all the lots, including the control lot, after 24 days of storage. The sample which was kept at 2°C in a controlled atmosphere for 12 days and then packed in a modified atmosphere of the same gas mixture did not exceed pH 7 after 31 days of storage, nor the limits of TVBN and TMA-N of 40 and 12mg per 100g respectively. As regards oxidative rancidity, TBA (2-thiobarbituric acid) levels were very low under all storage conditions and did not exceed 2.5mg malonaldehyde per 100 g muscle. According to the results of this study, bulk storage of whole gutted hake in boxes in ice under a controlled atmosphere could be combined with later packaging in a modified atmosphere on trays stored at 2°C to extend the shelf-life of the hake. © 2001 Society of Chemical Industry.