**3. Assay of cooked rice elongation**

Ten selected grains were soaked in distilled water for 30 min which were then placed between two pieces of wet filter paper in a petri dish filled with an appropriate amount of water. The dish was then placed in a covered container and the grains were cooked by steaming over boiling water for 10 min and simmering for 10 min (with power off). The cooked rice grain was transferred onto a piece of dry filter paper at the bottom of a fresh petri dish, which was placed in a desiccator with a constant temperature (19°C). Then the CRL was measured [11].

Ten randomly chosen intact polished grains were boiled in a water bath for 7 min after soaking in 7.5 ml of distilled water for 20 min. The cooked rice grains were then placed on absorbent paper for 15 min, and the boiled grain length (BGL, mm) and width (BGW, mm) were measured using the same scanner. The treatments were repeated twice, and the average grain length and width before and after cooking were calculated for estimation of elongation index.

The length of 10 whole rice kernels after cooking was measured by using the micro-scale, and the average kernel length determined. Kernel elongation ratio was calculated by dividing the average length of cooked kernel by the average length of the raw (uncooked) rice.

An inter-laboratory collaborative test was conducted for measurement of grain elongation of milled rice during cooking in 19 laboratories in 16 countries. Details of individual laboratory methods for measurement of grain elongation given below [9].

