Understanding the Influence of State/Phase Transitions on Ice Recrystallization in Atlantic Salmon (Salmo salar) During Frozen Storage

Abstract

Temperature fluctuations during storage and distribution of frozen foods lead to ice recrystallization and microstructural modifications that can affect food quality. Low temperature transitions may occur in frozen foods due to temperature fluctuations, resulting in less viscous and partially melted food matrices. This study systematically investigated the influence of state/phase transitions and temperature fluctuations on ice recrystallization during the frozen storage of salmon fillets. Using a modulated differential scanning calorimeter, we identified the characteristics glass transition temperature (T g ′) of −27°C and the onset temperature for ice crystal melting (T m ′) of −17°C in salmon. The temperature of salmon fillets in sealed plastic trays was lowered to −35°C in a freezer to achieve the glassy state. The temperature (T) of frozen salmon fillets in sealed plastic trays was modulated to achieve a rubbery state (T>T m ′), a partially freeze-concentrated state (T g ′<T<T m ′) and a glassy state (T<T g ′). We performed temperature modulation experiments by exposing packaged salmon to room temperature twice a day for 2 to 26 min during 4 weeks of storage. We also analyzed ice crystal morphology using environmental scanning electron microscopy and X-ray computed tomography techniques to observe the pore distribution after sublimation of ice crystals. Melt-refreeze and isomass rounding mechanisms of ice recrystallization were noticed in the frozen salmon subjected to temperature modulations. Results show that ice crystal growth occurred even in the glassy state of frozen salmon during storage, with or without temperature fluctuations. Ice crystal size in frozen salmon was greater in the rubbery state (T>T m ′) due to the increased mobility of unfrozen water compared to the glassy state. The morphological/geometric parameters of ice crystals in frozen salmon stored for 1 month differed significantly from those in 0-day storage. These findings are important to the frozen food industry because they can help optimize storage and distribution conditions and minimize quality loss of frozen salmon due to recrystallization.

Effect of temperature fluctuations on ice-crystal growth in frozen potatoes during storage

“…Enlargement of ice crystals, damages the internal fibrous structure of potatoes, and ultimately degrades the quality and reduces the storage life. A similar crystal growth was reported by Syamaladevi et al (2012) for frozen salmon and Ablett et al (2002) for frozen sugar solutions. Syamaladevi et al (2012) also reported that when the ice crystal size increases, the number of ice crystals decreased in salmon.…”

“…The transition of food from glassy to rubbery state and vice versa is unavoidable under freeze/ thaw conditions. The increased molecular mobility in rubbery state results in the enlargement of crystals and subsequent quality degradation (Syamaladevi, Kalehiwot, Balasigam, & Sablani, 2012). Glassy and rubbery states are important in frozen foods as the reactions are reduced to a large extent in the glassy state (Hagiwara, Mao, Suzuki, & Takai, 2005;Syamaladevi, Sablani, Tang, Powers, & Swanson, 2010).…”

“…Glassy and rubbery states are important in frozen foods as the reactions are reduced to a large extent in the glassy state (Hagiwara, Mao, Suzuki, & Takai, 2005;Syamaladevi, Sablani, Tang, Powers, & Swanson, 2010). The effect of freezing and thawing during storage has also been studied in meat, sea foods, ice cream and sugar solutions, which causes undesirable changes in texture of food (Adapa et al 2000;Hagiwara et al 2006;Mousavi, Miri, Cox, & Fryer, 2007;Syamaladevi et al, 2012).…”

Effect of osmotic dehydration pretreatment and glassy state storage on the quality attributes of frozen mangoes under long-term storage

“…However, there was a significant change of color (P \ 0.05) with storage time in the glassy state. This indicates that changes in the quality of food can occur, even when it is stored at a temperature below T g 0 , probably due to occurring enthalpy relaxation over time (Syamaladevi et al 2012). …”

“…This indicates that diffusion-limited reactions do not completely cease in the glassy state. Enthalpy relaxations may occur in frozen mangoes in the glassy state, resulting in molecular rearrangements and the diffusion of unfrozen water (Syamaladevi et al 2012). This may cause the growth of ice crystals through recrystallization during storage and further stress the fragile cellular structures of mangoes.…”