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Keywords:

  • Creep;
  • elasticity;
  • potato;
  • prediction of texture;
  • storage effect;
  • texture prediction

ABSTRACT

The relationship between texture of raw and cooked potatoes was studied. Tangent modulus of elasticity (E) using axial compression test and elasticity and viscosity parameters (E1, E2,η1 andη2) from creep tests were used as measures of texture on cylindrical test specimens. Raw potatoes were stored at 5, 15, 25C and variable temperature for 16 or 26 weeks and subjected to textural evaluation periodically in the raw state or after cooking at 90C for 25 min. The values of E decreased by about 50.0–74.0% and 42.0–68.0% for raw and cooked potatoes, respectively. The elasticity and viscosity parameters decreased by about 30.0–55.0% and 25.0–70.0% for raw and cooked potatoes, respectively. The changes in the texture of raw potatoes followed a systematic trend with storage temperature. However, such a trend in relation to storage temperature was not observed for textural changes in cooked potatoes. There was an apparent correlation between the textural parameters of raw and cooked potatoes irrespective of storage conditions (P < 0.05). Such relationships led to the estimation of textural parameters of cooked potatoes directly from textural measurements of raw potatoes regardless of the storage history with R2ranging from 0.70 to 0.87.