The effects of modified atmosphere and oxygen absorbant labels on the product quality of rainbow trout (Oncorhynchus mykiss, Walbaum 1972) fillets

In this study the effect upon the shelf life of Rainbow trout (oncorhynchus mykiss, Walbaum 1972) stored in refrigerated conditions (+4ºC) of the oxygen absorbent label (Fresh care) used in breads and other packaged foods was reserched. At the begining of the study the levels of crude protein, crude oil, moisture and crude ash analysis was performed and the results were found to be as follows, in the order above 19.16± 0.08, 10.32±0.08, 68.37±0.10, 1.75±0.14. On the first day of the trial, the determination of chemical quality, TVB – N, TBA, water activity performed and they were found as the above order 13.90±0.41mg/100g, 0.75±0.05 mgMDA/kg, 0.97±0.02. Looking at sensory analysis, it was observed that the control group's storage period (S) as compared with the other groups ( V, M, M+E ) attained lower sensory scores. The TVB – N showed an increase according to the storage, also the group with the oxygen absorbent label ( M+E ) compared with other groups ( S, V, M ) showed a lesser increase. The level of TVB – N were observed to reach: in group S on the 6th day was 37.20±0.99mg/100g, in the V group on the 19th day36.48±0.91mg/100g, in the M group on the 27th day 36.27±0.61 mg/100g, in the M+E group on the 32nd day 38.06±0.55 mg/100g. Depending on the storage the increasing TBA group change in S group on the 6th day was 0,75±0.05 mgMDA/kg, in V group on the 19th day was 1.31±0.02 mgMDA/kg, in M group on the 27th day was 1.57±0.01 mgMDA/kg, in M+E group on the 32nd day was 1.17±0.01 mgMDA/kg. At the start of the storage there an increase in the low mesophillic aerobic bacteria count in all samples. S Group on the 6th day 6.17±0.03 logkob/g, V group on the 19th day 6.33±0.01 logkob/g, M group on the 27thday 6.38±0.12 logkob/g, M+E group on the 32nd day 6.40±0.07 logkob/g were recorded. The total psychrophilic bacteria counts were recorded as follows, S group on the 6th day 6.08±0.04 logkob/g, V group on the 19th day 6.50±0.20 logkob/g, M group on the 27th day 6.15±0.15 logkob/g, M+E group on the 27th day 6.14±0.03 logkob/g. On examination of the data attained, the product packaged with MAP, passed the threashold levels of edibility earlier than product packaged with MAP+E and the difference between the results was found to be statistically important (p<0.05). It was observed that the oxygen absorbent label had a positive impact on the sensory and chemical qualities of the samples. Key Words: Rainbow trout, oxygen absorbent labels, modified atmosphere packaging, quality, shelf life