The comparison of the quality changes of the vacuum-packaged and plastic wrapped rainbow trout pastrami (Oncorhynchus mykiss, Walbaum 1792) stored at the refrigerator conditions

In this study, fish pastrami was made of rainbow trouts which were brought from a rainbow trout farm in Samsun into Fisheries Faculty, Fishing and Processing Technology Laboratory in Sinop University. Fish pastrami was sperated into two different groups (Group I. (S): Plastic wrapped, Group II. (V): Vacuum-packaged), refrigerated at 4oC. It was aimed that the determination of the shelf life of the fish pastrami by evaluating the biochemical composition, chemical, microbiological and organoleptic properties during the storage.Moisture, crude protein, crude fat and crude ash analyses were performed to determine the biochemical composition of the fish pastrami. These values were determined as 40,57%, 31,48%, 19,24%, 9,13% for the first day, 37,66±0,78%, 33,93±0,67%, 16,84±0,33%, 10,66±0,20% for the group S (Day 62), 42,21±0,26%, 28,53±0,39%, 24,99±0,45%, 8,55±0,17% for the group V (Day 77) at the end of the storage period respectively.TBA, TVB-N, activity of water (aw) and salt analyses were performed to determine the chemical quality parameters of the fish pastrami for the first day of the packaging and these parameters were determined as 4,86±0,06 mgMDA/kg, 24,54±0,36 mgN/100g, 6,33±0,01, 0,83±0,00, 10.73±0,15%. After the storage period these values were obtained as 5.81±0,07 mgMDA/kg, 35,26±0,64 mgN/100g, 6,13±0,01, 0,84±0,00, 8,29±0,07% for the group S (Day 62) and 5,78±0,06 mgMDA/kg, 35,46±0,51 mgN/100g, 5.99±0,01, 0,86±0,00, 9,63±0,17% for the group V (Day 77), respectively.Total Mesophilic Aerobic Bacteria (T.M.A.B), Total Psychrophilic Aerobic Bacteria (T.P.A.B), yeast and mould and coliform group bacteria count of the fish pastrami were determined as 4,48±0,01 logkob/g, 3,94±0,00 logkob/g, 4,88±0,01 logkob/g, 1,60±0,00 logkob/g for the first day of the packaging. After the storage, these values were calculated as 5,83±0,01 logkob/g, 5,30±0,02 logkob/g, 5,91±0,01 logkob/g, 2,18±0,03 logkob/g for the group S (Day 62) and 5,95±0,00 logkob/g, 5,28±0,02 logkob/g, 5,87±0,01 logkob/g, 2,34±0,02 logkob/g for the group V (Day 77), respectively.The fish pastrami was evaluated as appearance, smell, taste and texture as organoleptic characteristics over 10 points. These values of these parameters of the fish pastrami were graded by panelists as 9.6±0.24, 9.80±0.20, 9,40±0,40, 8,80±0,37 for the first day of packaging, after the storage; 7,60±0,24, 7,40±0,245,80±0,20, 6,40±0,24 for the group S (Day 62) and 5,20±0,20, 6,00±0,00, 6,80±0,20, 6,00±0,00 for the group V (Day 77), respectively.According to the results, plastic wrapped products exceeded the tolerable limits earlier tahn the vacuum-packaged products and the difference between them was found significantly important (p<0.05). Although the vacuum-packaged pastrami was stored for a long time showing good chemical properties, the packaging of the products with fenugreek was not found suitable in terms of organoleptic and microbiological properties because fenugreek mix becomes watery and this situation affects the microbiological load and organoleptic properties of the product.Key words: Rainbow trout, fish pastrami, vacuum packaged, refrigerated, shelf life