Rapid determination of nutrient composition and mineral element content of common vetch (Vicia sativa L.) using Near-infrared spectroscopy.

Objective: This study aims to establish an accurate and reliable near-infrared spectroscopy to enable rapid, efficient, and non-destructive evaluation of the nutritional quality of common vetches across different regions and varieties.

Methods: A total of 190 samples from various regions and varieties were selected for this study, which were divided into a calibration set (4:1 ratio) and validation set. The original spectrum of the calibration set is subjected to 10 different pretreatment techniques in combination with first and second derivatives, while the prediction model was established by combining the measured value of common vetch with the modified partial least squares method (MPLS).

Results: The results indicate that the calibration root-mean-square error (REMSEC) and cross-validation root-mean-square error (REMSECV) values range from 0.01 to 1.25 and 0.01 to 1.37, respectively. The determination coefficients of cross-validation (R2CV) for phosphorus (P), potassium (K), magnesium (Mg), and iron (Fe) are relatively low at 0.82, 0.86, 0.82, and 0.74 respectively; however, all other indicators have R2CV values above 0.90. The predicted root means square errors (RMSEP) for common vetch indexes range from 0.01 to 1.87 with RMSEP values higher than 1.0 observed for crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and ash indices, whereas RMSEP values lower than or equal to 1.0 were obtained for other indicators. The measured coefficient of determination (R2p) demonstrates that the R2p values for each nutrient element and mineral element vary from 0.70 to 0.96. The residual prediction deviation (RPD) values for Mg exhibit relatively low levels, while the RDP values for other indicators exceed 2.0.

Conclusion: These findings suggest that this study provides a viable approach to evaluate the nutritional composition and mineral element content of different varieties and regions of common vetch.