Analysis of amino and fatty acid composition in soybean seed, using near infrared reflectance spectroscopy

Soybean [Glycine max (L.) Merr.] is an important animal and human food source, mainly because of its high protein and oil concentrations. However, there is a need to improve the quality of soybean protein and oil. The objectives of this study were to (i), determine the potential use of near infrared reflectance spectroscopy (NIRS) for amino and fatty acid analysis in soybean seed and (ii) compare NIPS amino and fatty acid equations developed with ground-seed and whole-seed soybean samples. A total of 90 NIRS calibration samples and 26 NIPS validation samples were used for NIPS equation development and validation, respectively. AIL 116 soybean samples were grown at St. Paul and Rosemount, MN, in 1994 and 1995. Seventeen amino acid and five fatty acid NIPS equations for both ground-seed and whole-seed soybean samples were developed using the calibration samples. Validation of these NIPS equations showed a wide range for bias (-1.7 to 3.2 g kg(-1)), standard error of prediction corrected for bias [SEP(C)] (1.4 to 13.1 g kg(-1)), and coefficient of determination (R-2) (0.38 to 0.85) for all ground-seed NIPS equations, and a broad range for bias (-3.1 to 4.2), SEP(C) (2.6 to 17.8), and R-2 (0.06 to 0.83) for all whole-seed NIRS equations. It was concluded that NIPS could be used as a gross screening method for many amino and fatty acids contained in soybean seed. Additionally, NIPS was more accurate for amino and fatty acid analysis of ground-seed than whole-seed soybean samples.