Effect of temperature fluctuations during frozen storage on the quality of potato tissue (cv. Monalisa)

Results are presented on the effect of different ranges of temperature fluctuation (-24 to -18 degrees C, -18 to 12 degrees C, -12 to -6 degrees C, -24 to -12 degrees C and -18 to -6 degrees C) on the compression, shear and tension parameters of packed and unpacked frozen potato tissue. The initial temperature, duration and number (2, 4, 8, 16, 24 and 32) of fluctuations were varied. The highest parameter values occurred in samples subjected to fluctuations between -24 degrees C and -18 degrees C, and the lowest values in the range -18 to -6 degrees C. The mechanical strength of the frozen tissue decreased with an increase in the number of fluctuations and in most cases was lower in the packed samples. Moisture loss was greatest in the -18 to -6 degrees C range for pre-packed samples. Changes in the maximum compression force, as a measure mechanical damage, showed the greatest level of significance.