Effect of different packaging methods on shelf life of hot smoked rainbow trout (Oncorhynchus mykiss) during storage at 0-2oC

This study was carried out to investigate the effects of three different packing methods including modified atmosphere, vacuum and common packaging on chemical, microbial and sensorial quality and shelf life of hot smoked Rainbow trout (Oncorhynchus mykiss) during storage at refrigerated temperature. For hot smoking, rainbow trout were gutted and cut in butterfly form and washed. Fish gutted brining with 15% salt for 4 h and they were hot smoked by using Atmoos smoking cooking room. Then hot smoked samples were packed in modified atmosphere (with gas ratio of, N2:50%, O2:5%, CO2:45%), vacuum and common packaging and stored at refrigerated temperature (0-2ºC). Chemical values (total volatile basic nitrogen, moisture, peroxide, pH), microbial values (total microbial count, mold and yeast) and sensorial index (aroma, flavor, color and texture) were determined on 0, 10, 20, 30 and 40 days of storage. The results showed that samples did not have a significant difference in moisture and pH values (p>0.05), however significant different was found in peroxide, total count, mold and yeast and TVB-N values (p<0.05).Also, results of sensory evaluation have been showed that the score of color, flavor, texture and aroma in modified atmosphere packaging were more than other treatments (p<0.05). The Shelf life of the hot smoked trout is specified between 20 to 30 days, 30 to 40 days and at least 40 days in common, vacuum and MAP packaging, respectively. So, using the modified atmosphere for hot smoked trout can enhance quality and increase the shelf life of trout in refrigerated storage condition up to 40 days.