Differentiating vitreous and nonvitreous durum wheat kernels by using near-infrared spectroscopy

The vitreousness of durum wheat is used by the wheat industry as an indicat or of milling and cooking quality. The current visual method of determining vitreousness is subjective, and classification results between inspectors and countries vary widely. Thus, the use of near-infrared (NIR) spectroscop y to objectively classify vitreous and nonvitreous single kernels was inves tigated. Results showed that classification of obviously vitreous or nonvit reous kernels by the NIR procedure agreed almost perfectly with inspector c lassifications. However, when difficult-to-classify vitreous and nonvitreou s kernels were included in the analysis, the NIR procedure agreed with insp ectors on only 75% of kernels. While the classification of difficult kernel s by NIR spectroscopy did not match well with inspector classifications, th is NIR procedure quantifies vitreousness and thus may provide an objective classification means that could reduce inspector-to-inspector variability. Classifications appear to be due, at least in part, to scattering effects a nd to starch and protein differences between vitreous and nonvitreous kerne ls.