QUALITY EVALUATION OF US MEDIUM-GRAIN RICE USING A JAPANESE TASTE ANALYZER

Taste analyzers, developed in Japan, convert various physicochemical p arameters of rice into ''taste'' scores based on correlations between near-infrared reflectance (NIR) measurements of key constituents (e.g. , amylose, protein, moisture, fat acidity) and preference sensory scor es. These taste analyzers are being used by Japanese millers and whole salers to grade rice, both domestic and imported. This study examines the applicability of using the Satake Neuro Fuzzy Rice Taster for eval uating U.S. medium-grain rice cultivars. The Rice Taster, as presently calibrated, does not appear to be a valid tool for assessing rice cul tivars with low (<18%) amylose contents. The low-amylose cultivars fel l outside the range of the calibration set used by Satake. The effects of degree-of-milling and U.S. shipping practices on Rice Taster score s (S) were also determined. Conditioning of the bran during four weeks refrigerated storage led to the bran being more readily removed from the kernel during milling. This resulted in the milled rice having sig nificantly lower protein (P < 0.0001), free fatty acids (P < 0.01), an d n-hexanal (P < 0.0001) levels, increased whiteness (P < 0.0001) and milling degree (P < 0.0001) measures, and higher S (P < 0.0001) values . Deep milling significantly increased (P < 0.0001) chemical measures of amylose and significantly decreased protein and free fatty acids co ntents (P < 0.0001). Rice Taster measurements of ''amylose'' (A) and p rotein (B) significantly decreased (P < 0.0001) with deep milling. Moi sture (C), ''fat acidity'' (D-a), and milling yield (D-b) were not sig nificantly (P > 0.05) affected. S significantly (P < 0.0001) increased (mean 5 points) with deep milling.