Abstract
A new method to evaluate the texture and sensory attributes of cooked rice was studied in order to characterize the properties of cooked rice in which amylose content was low, under 15%. Measurement using a new model of tensipresser was carried out under two different conditions of low and high compression, using either the one-grain or mass-grain method. The properties of cooked rice in respect to strength, flexibility and fracturability were estimated from measurements at low and high compressions. A new cooking procedure which allows the measurement of these items after cooking without transferring to a measuring cup was applied to the mass-grain method. Four kinds of low-amylose rice, an aromatic rice, a large-grain rice and a high-yield rice were used as samples for comparison with Nipponbare as the control. Information as to firmness and adhesiveness of both the surface part and the whole grain was obtained from the physicochemical data of cooked rice measured by the one-grain method at low and high compressibilities. Thus, it was found that the physicochemical properties were significantly different between even the two kinds in which the amylose contents were only slightly different. Further, there were also significant differences in strength, flexibility and fracturability between the samples. The characteristics of each cooked rice in which the amylose content was lower than 15% could be clarified by the one-grain method. Moreover, similar results to those from the mass-grain method were obtained by the onegrain method. It was found that the new cooking procedures applied to the mass-grain method were useful for making uniform rice samples, as well as for convenient and rapid measurement. Thus, this new method is effective for measuring the texture of cooked rice, and there is a definite conelation between its sensory attributes and amylose contents and the structure of amylopectin.
