Determination of amino acids in wheat and barley by near-infrared reflectance spectroscopy

A study evaluated the utility of 2 research near-infrared reflectance (NIR) spectrometers and a commercial NIR spectrometer for the rapid screening analysis of 4 "limiting" amino acids in wheat, and up to 14 amino acids in barley. Spectral signals were recorded on 1 computerized research NIR spectrometer as log 1/R and transformed to the second-derivative of the signals for data analysis. This approach led to acceptable accuracies for the 4 wheat amino acids examined. For barley, high accuracy analysis was obtained for 13 amino acids using the other 2 NIR spectrometers with a first-derivative analysis method. NIR spectroscopy may be useful in amino acid analysis in plant-breeding studies, and in the food and feed industries for food analysis and protein quality evaluation. (wz)