Determination of amino acid nitrogen in tuber mustard using near-infrared spectroscopy with waveband selection stability.

Near-infrared (NIR) spectroscopy was successfully applied to the rapid chemical-free determination of amino acid nitrogen (AAN) in tuber mustard. Moving window partial least squares, combined with Savitzky-Golay smoothing, was used for the waveband selection. Based on the various divisions in the calibration and prediction sets, an effective modeling approach with good stability was proposed. The results confirmed that the long-wave NIR region contains sufficient information for the quantification of AAN in tuber mustard. An appropriate waveband (5874-4,258 cm(-1)) located in the combination region of NIR was selected. The validation root mean square error of prediction and the validation correlation coefficients of prediction were 0.380 mg/g and 0.962, respectively, both indicating good validation effect and stability. The results provided a reliable NIR model and can serve as valuable references for designing spectroscopic instruments for quality evaluation of tuber mustard.