Quality Changes in Chum Salmon (Oncorhynchus keta) Caviar (ikura) Affected by Thermal Pasteurization, Storage Time, and Packaging Material

Changes in quality parameters including pH, water activity, texture, and lipid oxidation were studied in pasteurized chum salmon (Oncorhynchus keta) ikura samples packaged using two films with different oxygen transmission rates (OTR) (40 and 62cm(3<bold>)m(</bold>-2<bold>)day(</bold>-1); F-40 and F-62), during 60days storage at 4 degrees C. No significant differences in pH and water activity (a(w)) were observed between ikura packaged using two different films with different OTR (P>0.05). However, compared to the first day of study, water activity decreased significantly in ikura (P<0.05). Ikura thiobarbituric reactive substance (TBARS) in the pouches significantly increased during the storage at 4 degrees C (P<0.05). Both pouches showed similar trends in TBARS until day 29, while after day 29, ikura packaged in F-62 (OTR=62cm(3<bold>)m(</bold>-2<bold>)day(</bold>-1)) showed a significant increase in TBARS compared to F-40 with less OTR (P<0.05). The texture of ikura became softer compared to the first day; however, no significant difference was observed between the ikura samples in two pouches (P<0.05). The quality changes of ikura measured during storage indicate that packaging ikura in a lower OTR film would provide greater quality retention than one with higher OTR.