Effects of modified atmosphere packaging (MAP) on quality and shelf life of dried spotted snakehead (Channa punctatus) products using an improved solar dryer

This study focused on follow-up the changes in the quality and shelf life of dried spotted snakehead (Channa punctatus) products under modified atmosphere packaging (MAP) conditions processed using an improved solar dryer. Four packaging methods, such as, air pack (sealed without changing atmospheric gas), MAP-1 (100% N2), MAP-2 (50% CO2 & 50% N2) and MAP-3 (40% CO2, 30% O2 & 30% N2) were employed and kept at room temperature. Biochemical and microbial analyses were performed at 15-days intervals over a period of 4 to 5 months of room storage. Moisture of the dried products remained within acceptable limits considering the salt content of the products. Observations revealed comparatively lower pH, total volatile base nitrogen (TVB-N), and thiobarbituric acid reactive substance (TBARS) values, none of which crossed the acceptable limits in any of the packaging conditions. Total viable counts (TVC) exceeded the permissible level of 5 log CFUg-1 after 75 days for air pack and MAP-1 samples and 120 days for MAP-2 and MAP-3 samples. Based on the bacterial counts, the shelf life of dried spotted snakehead products was estimated at approximately 75 days for air-pack and MAP-1 samples and 120 days for MAP-2 & MAP-3 samples. Therefore, MAP-2 (50% CO2 & 50% N2) & MAP-3 (40% CO2, 30% O2 & 30% N2) were identified as effective packaging methods for extending the shelf life of dried spotted snakehead products.