Impact of temperature fluctuations on quality changes of frozen green beans and carrots during storage

The quality of vegetables during frozen storage and distribution chain is affected by fluctuating temperature regimes. The temperature variations influence ice-water displacement due to ice crystal growth and ice-sublimation. Hence, the description of quality changes of frozen vegetables during temperature fluctuations is indispensable in the frozen food industry. In this context, frozen carrots and green beans were stored under four different temperatures: −8 °C ± 3 °C, −12 °C ± 3 °C, −18 °C ± 3 °C and −23 °C ± 3 °C for 12 months. In each storage condition, two different partitions were created to achieve different amplitudes of temperature fluctuations, namely low (±0.3 °C) and large (±2 °C). The evolution of frost forming and drip loss in green beans and carrots were analysed in addition to the changes of ascorbic acid in green beans. The results indicated that high mean storage temperature and large amplitude of fluctuation significantly affect the quality indicators. The quality data for drip loss and ascorbic acid were fitted to a first-order kinetic model. An Arrhenius model was applied to describe the temperature dependency by incorporating the temperature fluctuation scenarios. A simplified physical model was used to simulate frost formation during frozen storage in green beans and carrots. Finally, the models were validated using the data collected at −18 °C and −12 °C with low and large amplitudes of fluctuation.