Development of a texture profile following sensory analysis of cooked rice. Relationships between grain physico-chemical characteristics, instrumental measurement and sensory analysis of cooked rice

Seven commercial samples of raw-milled rice (3). and 4 differently parboiled rices (type 1 (2) and type 2 (2)) were used to study and to relate sensory perception to instrumental measurements. Analysis of variance was the statistical technique used to describe the difference between products. Principal component analysis was employed to reveal the links between sensory data and instrumental data and to show the rice sample plot Analysis of variance showed that the more discriminating characteristics were: thickness of cooked grain, length/width ratio, water uptake, elastic recovery, white core rate and amylose and protein contents. The most discerning attributes were: elasticity, length of grain, crunchiness, melting texture, compactness, stickiness, mealiness and pastiness. The PCA correlation circle showed high correlation between some sensory characteristics and instrumental measurements. Melting texture, surface moistness and juiciness, were positively correlated with water uptake (r=0.70, 0.61, 0.71). Granular texture, crunchiness, brittleness and mealiness, were significantly affected by white core presence (r=0.81, 0.74, 0.86, 0.83). Elasticity was dependant upon elastic recovery and firmness measured by the Viscoelastograph, but not linearly. Length of cooked grain was correlated with the length/width ratio of raw grain (r=0.78). Pastiness, compactness, stickiness were slightly influenced by the thickness of raw grain (r=0.82). To a weaker extent, firmness was associated with the firmness measured by the Instron (r=0.54). However amylose content was not correlated with any sensory attribute. PCA showed great differences in texture between rices. Two of them (first type of parboiling) were very elastic, another (second type of parboiling) was firm. granular, crunchy and mealy. The remaining two (second type of parboiling), cooked for longer. were moister and more melting. Among the 3 samples of raw-milled rices, differences in grain length feeling and melting- granular- brittle characteristics were distinguished. Unlike the amylose content, the technology effect (parboiling, cooking) and rice type seemed to be very important on sensory characteristics. (Résumé d'auteur)