Utilizing Near Infrared Reflectance Spectroscopy (NIRS) to Measure the Nutritional Composition of Oats

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Institute of Food Technologists Annual Meeting and Food Expo, Chicago, IL.


Oat is a unique cereal crop with significant health benefits. Knowing its nutritional composition is essential for decision making by oat breeders and food processors. The near-infrared reflectance spectroscopy (NIRS) technology provides a single analytical platform for the rapid and simultaneous measurement of multiple constituents. The aim of the research was to develop NIRS predictive calibration equation for simultaneous measurement of protein, oil, β-glucan, and total dietary fiber of oats. Separate equations were developed for ground and whole oat groats. Based on spectral analysis, a total of 640 oat samples from North American growing locations were selected for the equation development. Twenty percent of the total samples were randomly selected and designated as a validation set to test the accuracy and precision of NIRS measurements. Multivariate data analysis of the spectral data was performed. This included two processes namely spectral preprocessing and calibration model development. Modified partial least squares (PLS) method was used to develop the calibration models. For the reference analysis, crude protein was measured using the AACCI approved Dumas combustion method. Crude oil was measured using AOCS standard procedure. Enzymatic analysis of β-glucan was performed using the official AACCI method. Whole oat groat NIRS calibrations proved to be as effective as ground groat calibrations. Whole oat groat β-glucan calibrations yielded an excellent coefficient of determination (R2), standard error of calibration (SEC), standard error of cross-validation (SECV), and coefficient of determination of cross-validation (1-VR) values of 0.93, 0.18, 0.23, and 0.89, respectively. For protein calibrations of whole oat groats R2, SEC, SECV and 1-VR values were 0.89, 0.79, 0.85, and 0.87, respectively. The R2, SEC, and 1-VR values for the whole oat groats protein calibrations were further improved to 0.94, 0.77 and 0.92, respectively. For oil calibrations of whole oat groats, R2, SEC, SECV and 1-VR values were 0.90, 0.27, 0.30, and 0.88, respectively. We are expecting robust and effective predictive calibration equations for estimating total dietary fiber as well in the ongoing research. The use of whole oat groats as starting material represents a significant advancement in science as it precludes the need for sample grinding. R2 and 1–VR values approaching 1 mean that the NIRS technology may have the potential to be as robust and reliable as reference analysis itself. Achieving such a degree of accuracy from NIRS technology may preclude or limit the need for costly and time-consuming reference analysis.

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