Relationship between Physical Properties of Cooked Rice and Properties of Endosperm Starches of New Types of Rice Grains

The relationship between the physical properties of cooked rice and the properties of endosperm starches of new types of rice grains of 12 cultivars (15 samples) cultivated in 2001 at several places has been investigated by measuring the hardness and stickiness of freshly cooked and stale cooked rice using a Tensipresser, apparent amylose content, DSC thermograms, and RVA viscograms of the endosperm starches. The range of apparent amylose content of the endosperm starches of the new types of rice grains was 8.1-30.0%. There were highly positive relationships between the hardness of freshly cooked and stale cooked rice measured by a Tensipresser and the apparent amylose content, iodine affinity (blue value and wavelength at absorption maximum), and RVA setback, and highly negative relationships between the stickiness of freshly cooked and stale cooked rice measured by the Tensipresser. There were highly negative relationships between the hardness of freshly cooked and stale cooked rice measured by the Tensipresser and the degree of collapse and breakdown measured by RVA, and a highly positive relationship between the stickiness of freshly cooked and stale cooked rice measured by the Tensipresser.