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

•Freeze/thaw temperatures were selected based upon Tm′ of potatoes.•Number of pores decreased with increase in amplitude of temperature fluctuations.•Solid walls were damaged with increase in temperature fluctuations.•Smaller pores merged to larger pores with increase in temperature fluctuations.

Temperature fluctuation during storage and distribution of frozen foods has been a major concern for frozen food manufacturing industry. The fluctuation of temperature results in thawing and recrystallization of ice crystals, which is the main cause of frozen food quality degradation during storage. The effect of temperature fluctuations on ice recrystallization in frozen potatoes was investigated. Using micro computed tomography, growth in pore area due to increase in ice crystal sizes was determined. Four treatments (constant at −80 °C; and fluctuations between −17 to −16 °C, -17 to −11 °C and −17 to −7 °C) were used to observe their effect on pore size distribution. The growth of ice crystals with the increase in amplitude of temperature fluctuations resulted in damaging the microstructure of frozen potatoes. The damage pore solid walls resulted in reduction of the number of pores and increase in the size of pores.