RELATIONSHIP BETWEEN INSTRUMENTAL AND SENSORY PARAMETERS OF COOKED SWEET-POTATO TEXTURE

This study compared two instrumental methods, namely uniaxial compress ion and texture profile analysis (TPA), with sensory evaluation in des cribing the textural properties of cooked sweetpotatoes. The steamed c ooked samples (1.35 x 2.2 cm cylinder) of four cultivars and six selec tions were subjected to a trained texture profile panel for sensory ra tings and the two instrumental methods for determination of the mechan ical properties. Factor analysis indicated that the 15 sensory variabl es were grouped into 3 main factors, namely moistness-firmness (factor 1), particles (factor 2), and fiber (factor 3). Among the instrumenta l parameters, shear stress of compression and fracturability, hardness , and gumminess of TPA correlated highly (R = 0.73-0.95) with both the mouthfeel and mechanical-type sensory notes. These parameters of the two instrumental methods were linearly related (R-2 greater than or eq ual to 0.95) and could be converted from one to another with a high de gree of reliability. Regression equations based on shear stress signif icantly explained (R-2 = 0. 71-0.91) eight of the sensory notes. These instrumental parameters can be good predictors of cooked sweetpotato texture.