Proteolytic and Sensory Changes During Marination of Rainbow Trout (Oncorhynchus mykiss) Flesh in Pomegranate Juice

Suitability of pomegranate juice (PJ) alone or mixed with acetic acid versus acetic acid control solution, a traditional fish marinating media, was investigated in this research. With that purpose, rainbow trout fillets were marinated for 12 days at 4°C in one of three different marinating solutions: 100% acetic acid solution (AAS), 50% acetic acid/50% pomegranate juice solution (AAPJS), and 100% pomegranate juice solution (PJS). Moisture content and pH value of rainbow trout flesh decreased, whereas fat, protein, ash, and salt contents increased at the end of the marinating process for all treatments (p < 0.05). Fish flesh marinated in solution containing PJ had darker, more red and lower yellow color values due to migration of color components from the PJ (p < 0.01). Traditionally marinated fish flesh had the highest total free amino acid amount (p < 0.01) due to a higher level of proteolytic breakdown under the low pH condition, which could be seen on sodium dodecyl sulfate polyacrylamide gel electrophoresis image. This treatment also had higher sensory scores than those of fish marinated in solution containing 50% or 100% PJ. In addition, fish marinated in AAPJS and PJS solution had firmer texture and sweeter taste compared to that of marinated in AAS.