Quality Indicators of Northern Shrimp (Pandalus borealis) Stored under Different Cooling Conditions

The quality changes of northern shrimp, stored in ice, liquid-ice or salt-water ice at either -1.5 o C or 1.5 o C, were evaluated by using sensory assessment, chemical analysis, bacteriological test and physical methods. The main objective of this study was to identify freshness and quality indicators of Northern shrimp (Pandalus borealis) and to evaluate the efficiency of different cooling conditions. The total volatile nitrogen (TVBN) level in shrimp stored in liquid ice decreased during the first day of storage, and TVBN formation was delayed at least for 3 days for shrimp in liquid ice stored at -1.5 o C. In other shrimp stored in ice or salt-water ice, the TVB-N level increased with the time of storage. The trimethylamine (TMA) value increased gradually with storage time in all samples, except for the one stored in liquid ice at -1.5 o C during the first day of storage. The salt content increased rapidly in shrimp stored in liquid ice at -1.5 o C and increased slowly in other storage conditions, except for the iced shrimp where the salt content decreased slowly during the storage period. Water content increased gradually for all samples during storage. Texture showed only minor changes. Total viable counts (TVC) showed that bacteria grew most quickly in shrimp stored in ice and in salt-water ice, followed by those in liquid ice at 1.5 o C and -1.5 o C, respectively, throughout the storage period. Liquid ice storage at -1.5 o C gave the longest shelf-life of shrimp based on sensory analysis. Statistical analyses, principal component analysis (PCA) and analysis of variance (ANOVA), shows good correlation between, TVB-N, TMA, TVC, pH, NH3 response of electronic nose and sensory evaluation.