Author
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Kays, Sandra |
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Barton Ii, Franklin |
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Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/27/2002 Publication Date: N/A Citation: N/A Interpretive Summary: Distinct human physiological effects of insoluble and soluble dietary fiber have led to an increased interest in the amounts of these components in cereal food products. The amounts of insoluble and soluble dietary fiber present in a product are allowed to be included on the "Nutrition Facts" label as a sub-heading of dietary fiber, an option often utilized for products with health benefits. The analytical methods currently available to measure total, soluble, and insoluble dietary fiber are extremely time consuming, taking 2-3 days to complete a determination. Near-infrared reflectance spectroscopy is a rapid analytical method that relates the amount of light reflected from a substance, in the near-infrared region of the electromagnetic spectrum, to the amount of a certain constituent of the substance. Previous work has show that near-infrared spectroscopy can be used for the rapid and accurate analysis of total dietary fiber in a diverse range of cereal products. In the current study, near-infrared spectroscopy was investigated as a method of determining the soluble and insoluble dietary fiber content of cereal products. It was found that near-infrared spectroscopy can be used for the rapid and accurate determination of insoluble dietary fiber in a broad range of cereal products with wide variations in fat and sugar content. The accuracy of near-infrared determination of soluble dietary fiber appears to be limited by accuracy of soluble dietary fiber measurement using the currently available reference method in diverse cereal samples. A near-infrared approach would, however, be of utility for monitoring whether individual products are a good or poor source of soluble dietary fiber. Technical Abstract: Distinct human physiological effects of insoluble and soluble dietary fiber have led to an increased interest in the amounts of these components in cereal food products. This study explores the potential of using near-infrared reflectance spectroscopy for the rapid and accurate evaluation of both soluble and insoluble dietary fiber in a diverse group of cereal products. Products were obtained from retailers, ground (<500 um), and analyzed for soluble and insoluble dietary fiber using AOAC Method 991.43. Ground cereal samples were scanned with a scanning monochromator and spectra collected and processed using a commercial analysis program. A model was obtained (n=143) for the rapid and accurate determination of insoluble dietary fiber in cereal samples with diverse grains, processed by different methods, and containing large variations in fat and sugar content. The standard error of cross validation (SECV) was 1.5% and the multiple coefficient of determination was 0.98. Prediction of an independent group of cereal samples (n=62) resulted in a standard error of performance and coefficient of determination of 1.1% and 0.99, respectively. A model was also developed for the prediction of soluble dietary fiber in cereal products with low fat and sugar content. The model had a SECV of 1.1% and multiple coefficient of determination of 0.87. This model was expanded to include samples with high fat and sugar and the resulting SECV and multiple coefficient of determination were 1.2% and 0.82, respectively. Prediction of validation samples by the soluble fiber models resulted in a consistent bias which may be related to differences in the way the reference method treats samples with different soluble fiber constituents. |
