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ARS Home » Research » Publications at this Location » Publication #96920
Title: RICE QUALITY: WHAT CAN BE MEASURED?

Author
item Barton Ii, Franklin
item Himmelsbach, David
item Champagne, Elaine
item McClung, Anna

Submitted to: US Japan Nutritional Research Panel
Publication Type: Proceedings
Publication Acceptance Date: 3/20/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Rice is an important export crop, particularly to Japan, for American producers. However, American rice is considered to be of lower quality by the Japanese. If rice is to be marketed internationally, an objective set of standards must be developed. It is desirable for the determination of quality to be rapid, non destructive and spectroscopic. There are many different instruments capable of being used for these analyses. The emphasis to date has been on trying to model what is traditionally measured by reference methods for rice. This study examines those assays with respect to what we can see in the various spectra regions. Near Infrared and Raman are good for typical compositional analyses. One assay, that for apparent amylose, is not sufficiently precise to establish good chemometric models. A ratio of starch carbohydrates obtained by NMR spectroscopy may provide a better measure of rice quality.

Technical Abstract: Over the past 4 years a comprehensive research project has been conducted in collaboration with the Quality Assessment Research Unit and the Food Processing and Sensory Quality Research Unit. This project has looked at taste and texture of rice as effected by milling, moisture and drying regime. The use of Near Infrared Spectroscopy (NIRS) to develop rapid methods to assess rice quality is an integral part of this research effort Subsequently, a large data set of diverse rice samples was added to original study. Models for protein, apparent amylose, milling degree, whiteness and transparency were developed for five optical geometries. The Raman spectra of these samples was obtained and models developed for protein and apparent amylose. Solid State proton Nuclear Magnetic Resonance was employed to determine the ration of alpha 1-6 to alpha 1-4 linkages in the amylose/amylo-pectin fraction. It is believed that this may give a better measure of the amylose/amylo-pectin contribution to rheological properties. These data will be discussed to show where rice research to assess quality can go in the future.