Acta Vet. Brno 2012, 81: 397-402
The effect of glaze and storage temperature on the quality of frozen mackerel fillets
The effect of glazing and storage temperature on lipid oxidation and sensory properties of mackerel fillets was evaluated. A total of 288 fillets were stored for 6 months under stable temperature of –18 °C and unstable temperature, which involved six temperature fluctuation cycles from –18 to –5 °C each month. Glaze determination, chemical composition, thiobarbituric acid reactive substances examination and sensory evaluation of fillets were performed. Glazing and stable temperature conditions slowed down lipid oxidation in fillets compared to unglazed samples and samples stored under unstable freezing conditions. The thiobarbituric acid reactive substances increased slowly in glazed samples and a positive effect of stable conditions was found after two months and became obvious from the fifth month of storage. Sensory scores included evaluation of taste, aroma, texture, juiciness, and appearance corresponded to chemical results. Glazed fillets had the best scores in sensory evaluation and can be recommended for consumption; on the other hand, unglazed fillets stored under unstable temperature could not be consumed because of rancidity. This is the first similar study in mackerel when unstable temperature conditions are considered as a factor increasing lipid oxidation. Prevention of temperature fluctuation during storage is important to keep the quality of the frozen fillets.
