GLASS TRANSITION OF RAINBOW TROUT AND EFFECT OF CRYOPROTECTANTS ON SOME CHANGES

Sucrose (2%), sorbitol (2%), mannitol (2%), gum arabic (0.15%), carrageenan (0.15%) 8 and meat stabilizer (0.5%) were blended with ground rainbow trout and stored for 6 months separately at -9, -13C (glass transition temperature [T-g] of rainbow trout determined by differential scanning calorimetry) and -18C. Total volatile basic nitrogen (TVB-N) and thiobarbituric acid-reactive substances (TBARS) were determined at first, third and sixth months of storage periods. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was conducted on isolated myofibrillar proteins for first, third and sixth months. Biopolymers and storage period had a significant effect (P < 0.05) on the TVB-N and TBARS values. T-g (-13C) and -18C showed the same effects on TVB-N and TBARS values, but -9C had statistically different effect on them. SDS-PAGE characteristics of myofibrillar proteins revealed that the samples with gum arabic, sucrose and sorbitol were different from the other samples.