Skip to main content
ARS Home » Research » Publications at this Location » Publication #123908
Title: RAPID VISCOANALYZER PARAMETERS BY NEAR INFRARED REFLECTANCE SPECCTROSCOPY AND TWO-DIMENSIONAL CORRELATION

Author
item MEADOWS, FREDERICK
item BARTON II, FRANKLIN

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2002
Publication Date: 7/31/2002
Citation: N/A

Interpretive Summary: RVAs (Rapid Visco Analyzers) are widely used in assessing the cooking and processing qualities in grains. However, the analysis time limits the method. In order to shorten the time needed determine cooking and processing qualities, a novel noninvasive rapid approach has been tried. We have used NIR spectroscopy to predict the traditional RVA parameters, but they are unable to be predicted precisely. Therefore, we have derived a new parameter using PLS2 calculations that may be used in lieu of, or in conjunction with the current RVA measures for cooking qualities.

Technical Abstract: Currently, RVAs (Rapid Visco Analyzers) are widely used in assessing cooking and processing characteristics in rice. But, the traditional parameters measured by an RVA rely on the rate of gelatinization that varies with rice content. A novel parameter that avoids this dependence was sought. A parameter, whereby time and temperature are not components, may be correlated more easily with NIR spectroscopy. A total of 86 cultivars containing short, medium, and long grain rice were used for NIR and RVA measurements. The content of amylose ranged from 0.41% to 24.90% (w/w) and that of protein ranged from 8.47% to 11.35%. Moisture in rice flour samples was approximately 12%. Amylose and protein concentrations were used in PLS1 (Partial Least Squares Regression) models consisting of both RVA and NIR data. Similarly, NIR absorptions and RVA viscosities were used in a PLS2 regression model. The PLS2 model resulted in the construction of a two-dimensional (2D) matrix map of regression coefficients. Using this calculation, the viscosity in the region near 216 seconds (sec) (at and temperature 80 deg C +/ 1 deg C) was found to vary linearly (r**2=0.959 calibration, r**2=0.916 validation) with the NIR (1,100-2,500 nm) spectrum.