The Determination of Quality Changes of Vacuum-Packaged Rainbow Trout (Oncorhynchus mykiss) Surimi Stored in the Refrigerator

Abstract

This study is aimed to determine the chemical composition and the shelf life of the rainbow trout (Oncorhynchus mykiss) being turned into surimi in the refrigerator conditions. The trout taken from a rainbow trout (Oncorhynchus mykiss) farm situated in Rize are brought to the laboratory of Rize University Faculty of Aquaculture, and their head and internal organs were cleaned out, then they are flayed. The fish turned into fillet were ground in the grinder (3 mm). After one day, starch 4%, sugar 3%, salt 1.5%, sorbitol 0.3% are added into the filtered mince and mixed. Then, each approximately 250 g, 8 pieces as vacuum packaged were kept in the refrigerator conditions (4±1°C) throughout the analysis.With the aim of examining the change in the nutritional value and the quality during 4°C storage of surimi, organoleptic and chemical analyses are carried out periodically (10 days). In the sample of surimi kept in the refrigerator vacuum packaged, the starting TVB-N, TBA, TMA amounts in order were determined as 7.01 mg/100 g, 0.55 mg malonaldehyde/kg, 0.18 mg/100 g. These values have increased through the storage, and spoiled in the 68th day by exceeding the limit value according to the TVB-N criteria. In the day of spoilage, both the TBA value measured as 4.51 mg malonaldehyde/kg and TMA value as 2.68 mg/100 g have stayed in the allowed limit values. At the end of the 50th day, as a result of the points that a panellist group of 6 people gave organoleptic, the trout surimi has fallen under the consumption limits according to taste criteria.