Comparison shelf life and sensoryevaluation of Otolithes ruber (whole, gutted and fillet) in a vacuum packaging at -18oC

The purpose of the this study is to compare the shelf life of Otolithes ruber (whole, gutted and fillet) in a vacuum packaging during four months of storage in freezing condition at -180C. The biochemical indicators(pH, free fatty acids, thiobarbituric acid, total volatile nitrogenous bases, peroxide), microbialand sensory evaluation assessmentsof the fish were carried out at the end of each month. According to the statistical results, with the increase of the shelf life, there was no significant difference between the pH in the studied treatments (P>0.05). The content of TBA and FFA in all storage time had an ascending trend. The maximum change of TVB-N was related to the whole fish, so that it reached from 10.46 to 26/72 mg/ 100g at the end of the storage. In all the treatments, the level of PV didn't exceed the standard limit (10-20 mEq/kg). There were significant differences between the PTC count in the three treatments during this time (P<0.05) and exceed the standard limits of 7 log cfu/g by the end of the period. According to the sensory evaluation, the fillets had a suitable quality by the end of the fourth month of storage. According to the microbial experiments and the chemical spoilage indexes, the fish in the form of fillet, whole and gutted in a vacuum packaging at -180C had a desirable quality by the end of the storage (4 months) and didn’t exceed the reported standard limits.