Rice and easy standard texture measurement

Rice remains a primary dietary staple for a large proportion of the global population and is also widely used as an ingredient in processed and convenience foods. For breeders, processors and manufacturers, matching a rice cultivar to a target eating profile is a non-trivial formulation and quality-control problem. With more than 1,000 recognised varieties, differences in amylose content, gel consistency and gelatinisation behaviour can produce substantial variation in cooked texture, including firmness, stickiness and cohesiveness.

Because these attributes directly influence consumer acceptance, there is a clear need for objective, repeatable methods that complement or reduce reliance on sensory panels.

Standardised instrumental method

The publication of ISO 11747 established a standardised procedure for the instrumental assessment of cooked rice texture. In response, Stable Micro Systems developed a Rice Extrusion Rig for use with its Plus range of Texture Analysers, designed to conform to the dimensional and procedural requirements of the standard.

The method enables growers, processors and food manufacturers to quantify the resistance of cooked rice to extrusion under controlled test conditions. This provides an objective basis for comparing cultivars, validating process conditions and selecting products that meet defined sensory and market requirements.

Why the method matters

Palatability is influenced by multiple factors, including aroma, flavour, appearance and texture, but texture is often the most difficult to assess objectively. Sensory testing remains valuable, yet it is time-consuming, labour-intensive and inherently variable between panellists, sites and regions.

This challenge is particularly relevant in rice because preferred texture profiles differ significantly across markets. In the Middle East and South Asia, consumers often favour drier, more separate grains. In Japan, the Republic of Korea and northern China, softer and more adhesive textures are generally preferred. Instrumental measurement does not replace sensory assessment, but it allows manufacturers to screen samples rapidly, establish quantitative acceptance criteria and monitor batch-to-batch consistency before confirmatory sensory work.

Standard development and reproducibility

ISO 11747 emerged from interlaboratory work organised in 2010 by UNI and involving nine international laboratories, under the oversight of ISO/TC 34 for cereals and pulses. That collaborative validation is important because it supports method reproducibility across laboratories, instruments and operators, which is essential for specification setting, supplier comparison and quality assurance.

For technical users, standardisation also improves confidence in data interpretation. When sample preparation, fixture geometry and analysis parameters are defined, differences in measured extrusion resistance are more likely to reflect true material behaviour rather than procedural variation.

Practical implications for industry

The Rice Extrusion Rig offers a relatively fast, simple and cost-effective method for characterising cooked rice texture. Additional design features intended to simplify removal and replacement of the test cell between runs can also improve throughput in routine laboratory environments.

For R&D and quality-control teams, the method supports several practical applications:

• Cultivar selection against target texture specifications

• Verification of processing effects, including parboiling and cooking conditions

• Benchmarking of raw material lots

• Support for product development in region-specific markets

• Reduction in dependence on lengthy sensory trials during early screening

By combining instrumental data with sensory evaluation, manufacturers can build a more robust understanding of how composition and processing influence the final eating experience.