The Effects of Type of Vacuum Packaging and Additives on the Oxidative Stability of Skinless Frozen Rainbow Trout Fillet (Oncorhynchus mykiss)

Researchers are always looking for ways to maintain the food quality. In this study the effects of two types of packing (Conventional and Vacuum) and additives that contain oregano extract and sodium tripolyphosphate (2%) individually and in combination, were investigated on the quality of rainbow trout fillets without skin during 6 months of storage at -18 ° C.
This survey consisted of five treatments. Sampling were performed at 0 and 1, 2, 3, 4, 5 and 6 months to determine some chemical (thiobarbituric acid, free fatty acid and water holding capacity), sensory and tissue analyses.
Chemical examination of the samples indicated that conventional packing containing sodium tripolyphosphate and additive mixture with oregano had better performance in reducing thiobarbituric acid as well as good effect concerned with vacuum packing in respect of free fatty acids reduction as compared to the control. Dripping in tripolyphosphate treatment was lower than additive mixture. Treatment concerned with sodium tripolyphosphate indicated better results regarding sensory characteristics as compared to the treatment with added oregano extract and control.
The application of polyphosphate as an additive in vacuum packaging might be regarded as an effective method to maintain the quality of rainbow trout fillets stored at -18°C for 6 months.