DETERMINATION OF GLASS TRANSITION TEMPERATURE OF RAINBOW TROUT ( ONCORHYNCHUS MYKISS ) AND EFFECTS OF VARIOUS CRYOPROTECTIVE BIOPOLYMER BLENDS ON SOME CHEMICAL CHANGES

Sucrose  +  sorbitol  +  gum arabic (2  +  2  +  0.15%), sucrose  +  sorbitol  +  carrageenan (2%  +  2%  +  0.15%), sucrose  +  mannitol  +  gum arabic (2%  +  2%  +  0.15%), sucrose  +  mannitol  +  carrageenan (2%  +  2%  +  0.15%), sorbitol  +  mannitol  +  gum arabic (2%  +  2%  +  0.15%) and sorbitol  +  mannitol  +  carrageenan (2%  +  2%  +  0.15%) were blended with ground rainbow trout and stored at glass transition temperature ( T g ) of rainbow trout ( − 13C), determined by differential scanning calorimetry at − 9 and − 18C for 6 months. Total volatile basic nitrogen (TVB‐N) and thiobarbituric acid‐reactive substances (TBARS) were determined at 1st, 3rd and 6th months of storage periods. Biopolymer blends and storage period had a significant effect ( P <  0.05) on the TVB‐N and TBARS values. T g and − 18C showed same effect on TVB‐N and TBARS values but − 9C has statistically different effect on them.PRACTICAL APPLICATIONS The T g value was found as −13C for rainbow trout. This value is higher than commercial storage temperature (−18C). This has a great importance in terms of economical viewpoint. It was determined that TVB‐N values were same and TBARS values were similar at the end of 6 months storage at T g and −18C. When considering these two parameters, it can be accepted that −13C could be an indicator of usability instead of −18C.