Assessment of bioactive compounds in faba bean using infrared spectroscopy

Abstract

Faba bean (Vicia faba) is growing in popularity in Australia, partly due to its higher levels of health-benefiting compounds compared to other grain crops. This study investigated infrared spectroscopy for predicting levels of bioactive compounds such as antioxidants and phenolics in faba bean flour. Calibration models were performed on 60 samples of faba bean, comprising 10 varieties grown across two field locations in 1 year. For model validation, an independent test set comprising the same varieties grown in a different year was utilised. Near-infrared spectroscopy (NIRS) showed promise for the prediction of total phenolic content, with an R²_pred of 0.66 and root mean square error of prediction (RMSEP) of 76 mg/100 g. Similarly, prediction of ferric reducing antioxidant power, a measure of antioxidant activity, gave an R²_pred of 0.59 and RMSEP of 87 mg/100 g. Additionally, moving window optimisation was used to determine the most important wavelength region for the prediction of these analytes. Fourier transform infrared spectroscopy did not yield any suitable models for the analytes investigated. Although the NIRS models developed were not capable of exactly quantifying phenolic or antioxidant content, infrared spectroscopy appears useful for rapidly discriminating between samples containing high and low levels of phenolics or antioxidant compounds. With further refinement, this technique could potentially be applied for the quality assurance of phenolic content or antioxidant capacity in faba bean seeds.