160 Textural properties of six varieties of cooked waxy rice.

Y. MOCHIZUKI (1), W. H. Yokoyama (2), and C. F. Shoemaker (1). (1) Dept. of Food Science and Technology, University of California, Davis, CA 95616; (2) U.S. Department of Agriculture, ARS, Western Regional Research Center, Albany, CA 94710.

Texture of 6 cooked waxy rice varieties, Calmochi-101 from California, Hakucho-mochi, Hiyoku- mochi, Himeno-mochi from Japan, Indica type from Thailand, and Japonica type from southern China, were evaluated using an uni-axial compression test, a texture profile analysis, and a low (25% of sample thickness) and high (90%) compression test using a Tensipresser, single kernel analyzer. In order to determine rice soaking time, Calmochi-101 and Hakucho-mochi were soaked in water at 5, 15, 25 C and moisture content was determined several times over 24h. Each rice variety was boiled using 3 different water ratios to avoid an influence of cooking water ratio and then stored at ambient temperature. Calmochi-101 and Hakucho-mochi were also steamed and stored at 15 C. For the first 3 hours soaking, milled rice of Calmochi-101 absorbed water faster than Hakucho-mochi, after that both varieties were saturated with the same moisture content. Boiled rice samples had similar hardness at 1h and 24h after cooking. However, Indica type from Thailand and Japonica type from China had significantly lower stickiness than others at 1h after cooking. Steamed Calmochi-101 and Hakucho-mochi were similar in hardness and stickiness until 12h after cooking. However, Calmochi-101 became harder and less sticky than Hakucho-mochi at 24h after cooking.