February 26/Science Letter -- According to a study from the U.S., "Degree of milling (DOM) of rice plays a key role in determining rice quality and value. Therefore, accurate, nondestructure, quick, and automated surface lipid content (SLC) measurement would be Useful in a commercial milling environment."
"This study Was undertaken to provide calibration models for commercial use to provide quick and accurate evaluation of milled rice SLC and Hunterlab color parameters (La,h) as indications of rice DOM. In all 960 samples, including seven cultivars front seven southern U.S. locations, stored for zero, one, two, three and six months, were milled for four durations to obtain samples of varying DOM. The samples were used to develop calibration models of milled rice SLC and L,a,b values. Another sample set (n=58) was commercially milled and used to validate the developed models. A DA 7200 diode array analyzer was used to scan milled rice samples in wavelength spectra of 950-1,650nm. SLC and color parameters were measured using a Soxtec system and a HunterLab colorimeter, respectively. The partial least squares repression (PLS) method using the full near-infrared spectra was used to develop prediction models.
For rice SI-C and color parameters. Milled rice SLC was well fitted with a correlation of determination of predicted and measured values CS of (R-2=0.934). Color parameters were also successfully fitted for L (R-2=0.943), a (R-2=0.870), and b (R-2=0.855)," wrote M.I. Saleh and colleagues, University of Arkansas (see also Cereal Chemistry).
The researchers concluded, "Performance of the developed models to predict rice DOM was superior in predicting SLC and L,a,b values with R-2 predicted and measured values of 0.958, 0.836, 0.924 and 0.661, respectively."
Saleh and colleagues published their study in Cereal Chemistry ("Development and Validation of Prediction Models for Rice Surface Lipid Content and Color Parameters Using Near-Infrared Spectroscopy: A Basis for Predicting Rice Degree of Milling." Cereal Chemistry, 2008;85(6):787-791).
For more information, contact J.F. Meullenet, University of Arkansas, Dept. of Food Science, 2650 N Young Avenue, Fayetteville, AR 72704, USA.
From the February 16, 2009, Prepared Foods E-dition