Nondestructive measurement of anthocyanin in intact soybean seed using Fourier Transform Near-Infrared (FT-NIR) and Fourier Transform Infrared (FT-IR) spectroscopy

The content of phytochemical compounds such as anthocyanin in soybeans, yielded from agricultural practices is usually affected by the quality of the mother seed. Therefore, non-destructive technique for intact soybean seed selection based on anthocyanin content is highly demanded for breeding programs. The objective of this study was to evaluate the feasibility of Fourier-transform near-infrared (FT-NIR) and Fourier-transform infrared (FT-IR) spectroscopic techniques to determine the total anthocyanin content (TAC) and content of different types of anthocyanin, namely cyanidin-3-glucoside (C3G) and delphinidin-3-glucoside (D3G), in single seed state of soybean. FT-NIR and FT-IR spectra from 70 different varieties of soybean seeds were acquired and compared with the chemical components analyzed using high-performance liquid chromatography (HPLC). The prediction performance of the partial least squares regression (PLSR) models for the FT-NIR spectra indicated R2 of 0.88–0.90 and standard error of prediction (SEP) of 9.4–19.5% for the chemical components, which were slightly better than R2 of 0.86–0.88 and SEP of 9.7–21.8% of FT-IR. The number of variables could be reduced down to 50% using a variable importance in projection (VIP) method without noticeable decrements in prediction performance. The results demonstrated potential of FT-NIR and FT-IR spectroscopic techniques to predict anthocyanin contents in a single seed of soybean nondestructively.