Instrumental and sensory characterization of cooked potato texture

Uniaxial compression, Texture Profile Analysis (TPA) and chemical measureme nts were related to sensory texture evaluation of potato quality during sto rage. Principal component analysis grouped the varieties into three types o f variation: mealiness versus firmness and springiness (PCI), moistness ver sus adhesiveness (PC2) and hardness versus adhesiveness and moistness (PC3) . In uniaxial compression the variable 'stress', 'work up to fracture' and 'total work during compression' described the same type of information in t he delta. These uniaxial data and most of the TPA data were highly correlat ed. Uniaxial compression data (stress, strain, modulus of deformability), s tarch structural data (area, roundness, aspect ratio), specific gravity and pectin methyl esterase activity discriminated between the varieties and ha rvest times. Partial Least Squares Regression showed stress, strain, modulu s of deformability, and specific gravity to be the most important variables in distinguishing between two groups of sensory texture attributes explain ing 65% of the total variance in the sensory data. Coefficients of correlat ion between predicted and measured sensory attributes were in the range 0.3 6-0.79. The TPA data were not found to be relevant substitutions for the se nsory attributes.