Comparison of Commercial near Infrared Transmittance and Reflectance Instruments for Analysis of Whole Grains and Seeds

TLDR

The study compared NIR transmittance and reflectance instruments for measuring protein, oil, moisture, and other constituents in commercial grains and seeds, using RPD statistics and whole‑grain versus ground‑grain calibration monitoring. Both transmittance and reflectance methods showed comparable accuracy and reproducibility, and optimizing the wavelength range improved measurements in both NIR and visible/NIR spectra.

Abstract

Near infrared transmittance and reflectance instruments were compared for the determination of protein, oil, moisture and some other constituents and parameters in several grains and seeds of commerce. Both approaches were comparable in accuracy and reproducibility. The importance of optimisation of the wavelength range in whole grain analysis is demonstrated for measurements in both the NIR and visible/NlR wavelength ranges. The RPD statistic, which relates the standard error of prediction to the standard deviation of the original data, is illustrated as a method for the evaluation of calibrations. The concept of monitoring the accuracy of analysis using whole grain calibrations with ground grain calibrations is introduced.