Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 17, 1999
Publication Date: N/A
Interpretive Summary: Measurement of texture quality by sensory and instrumental procedures is important because rice and rice products are increasingly popular and in demand by globally diverse cultures. This demand is expanding the global markets for U. S. rice, creating the need for better methods to quickly evaluate rice and predict end-use quality. This study examined the relationships between two modes of measuring texture attributes of rices: sensory panels and instrumental texture analyzers. Texture characteristics of six rice samples that differed by variety, growing location and post harvest handling were evaluated. Correlations between individual sensory descriptive attributes and instrumental texture parameters were weak. Instrumental parameters did not measure the same parameters that were described as the important sensory attributes. Sensory analysis was more sensitive than instrumental texture tests in detecting subtle texture changes such as stickiness and adhesiveness. The implication of these subtle, yet detectable differences, makes it all the more important to find sensitive methods that can provide rapid assessments and prediction of quality. Additional work is needed to develop instrumental methods for rice evaluation that correlate with sensory concepts.
Technical Abstract: Texture attributes of cooked rice and ways to measure these attributes by sensory and instrumental methods are receiving attention because of the increased popularity of rice and rice products by globally diverse cultures. Many factors influence cooked rice texture, including cultivar, physico-chemical properties, postharvest handling practices (milling degree, drying conditions, and final moisture), and cooking method. Information on the relationships between sensory, physical and chemical characteristics will lead to better methods to quickly evaluate and predict the end-use qualities that will help to match the rices with specific characteristics to the populations that demand those attributes. This paper reports the relationships between two modes of measuring texture attributes of rices: sensory and instrumental texture analyzers. Six medium and short grain rice samples, differing by variety and/or growing location, were dried to achieve final moisture levels of 12 or 15% and then regular or deep milled (n=120). Correlations between individual sensory descriptive attributes and instrumental texture profile attributes were weak. Of only twelve significant correlations, the highest value was r=0.624. Combined sensory and instrumental data were factor analyzed. This analysis revealed that sensory attributes still accounted for the most variation (35.32% out of 76.55%). Sensory descriptive analysis was more sensitive to subtle changes in initial texture perception that included parameters relating to stickiness and adhesiveness. The two-cycle compression test for texture profile parameters (i.e. fracturability, hardness, cohesiveness, adhesiveness, gumminess, springiness, and chewiness) accounted for less variation in the data on texture differences.