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The texture of 10 milled rices cooked by a standardized method in excess water was measured in 11 laboratories using various instrument methods that had been developed specifically for national samples. The samples selected represented a wide range of rice textures. Instrument indexes for hardness and stickiness of cooked rice generally were more sensitive than the corresponding taste panel scores in discriminating among the 10 cooked rice samples. Instrument indexes for hardness correlated positively among each other as did those for stickiness. Most hardness indexes showed significant negative correlation with stickiness indexes. Most hardness indexes were positively correlated with amylose content whereas stickiness indexes were negatively correlated with amylose content. The continued use of amylose content as an index of eating quality in a rice breeding program is justified.' Chairman-organizer of the Cooperative Testing. Journal of T e x t u r e S l u d i e s 1 2 (1981) 17--38 A 11 Righls Rcseroed W o p y r r p h l 1981 by Food Q Nulrrtion Press. Inc , Wc,slporl, Conneclicul E ! z c M U 0 3 z 0 " m c3 ' Based on oven moisture method except cooperator 1 which was based on increase in weight of cooked rice uncorrected for solubles

The rheological properties of several samples of guar gum and locust bean gum, characterized by light scattering and intrinsic viscosity measurements, were studied. The flow curves of concentrated solutions were obtained with a cone‐plate viscometer and their viscoelastic properties were measured with a concentric hemispheres viscoelastometer. The two flow‐units Ree‐Eyring model and the Cross equation gave a good fit to the experimental flow curves. The zero shear rate viscosity, and the relaxation time, of the Ree‐Eyring model depend mainly on the reduced concentration c[η]. This result, as well as the viscoelastic properties, indicate that entanglements play a dominant role in concentrated solutions. From a practical viewpoint, it is possible to predict the flow curve of a galactomannan solution at any concentration if the intrinsic viscosity of the sample is known. However, there are secondary differences in the flow parameters, mainly in the relaxation time, which are not ascribed to [η]. It is hypothesized that these differences are due to the mean branching degree rather than to the botanical origin. As, in solution, the smoothest galactomannan macromolecules are more probably aggregated than isolated, further work should aim at establishing the relationships between aggregate formation and degree of branching.

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