Extension of shelf-life of ready-to-cook (RTC) pangas fish (Pangasianodon hypophthalmus) curry by modified atmosphere packaging at chilled storage

Abstract

Ready-to-cook (RTC) fish products are getting popular due to busy lifestyle of the people. However, preservation is a big concern for these types of perishable food items. Modified atmosphere packaging (MAP) is a widely used packaging technique used for displaying chilled fish and fishery products in developed countries. In light of this, the quality and shelf-life of RTC pangas fish (Pangasianodon hypophthalmus) curry was evaluated by biochemical and microbiological analysis under not sealed pack (control), MAP-1 (50% CO2 & 50% N2) and MAP-2 (75% CO2 & 25%N2) pack at 4 days interval during 20 days of storage at 4°C. The pH value of pangas fish curry was in the range of 6.01 to 6.80 during the storage period. The total volatile base nitrogen (TVB-N) value in fish curry gradually increased with the storage time. However, there were no significant (p<0.05) differences in pH and TVBN values among all packaging conditions during storage. Thiobarbituric acid reactive substances (TBARS) fluctuated between 0.03 to 0.56 mg malonaldehyde/kg during the storage period. The pH, TVB-N and TBARS values under all packaging conditions were within the acceptable limit during the storage period. The total viable count (TVC) gradually increased with time in all packaging conditions. However, significantly (p<0.05) lower TVC values were observed on the 12th and 16th day of storage in all samples compared to that of the control sample. Considering the bacterial counts, the shelf-life was determined at approximately 9 days for not sealed pack, 13 days for MAP-1, and 15 days for MAP-2 sample, based on the 7 logs CFU/g, which is considered as the upper acceptable limit for fresh and frozen fish. Therefore, the MAP-2 (75% CO2 & 25%N2) is the best packaging, which can be utilized by the superstores to display this kind of value-added products with extended shelf life.