Study the effect of packaging system on shelf life of rainbow trout

The effects of three types of common packaging in Iran on rainbow trout quality during storage time were studied. Fish samples after evacuation of offal and preparation were classified into 4 treatments: treatment 1 (without packaging; control), treatment 2 (vacuum), treatment 3 (skin pack), treatment 4 (stretch film). After packaging the samples were, respectively, kept in refrigerating rooms with 1°C temperature (for a week) then -18°C temperature by the end of the period of studied. At first, the amount of compositions of protein, fat, ash, moisture, and carbohydrate were measured in primary fish (control). Also, all assessments were performed after 0, 15, 30, 45 and 60 days of storage with 5 repetitions for each experiment including: chemical (pH and PV) and sensory (taste, aroma, tissue, color, and overall appearance) properties. The results showed that the amount of PV increased in all treatments meaningfully (0-90 mEq O2/kg). Among the treatments, skin pack had the lowest and the highest amount of PV (4 mEq O2/kg) and pH (6.25), respectively, by the end of the period. The results of sensory assessment showed that the sensory scores of all treatments decreased and by the end of the period only vacuum packaging was acquired the highest scores.