Detection of low-level gluten content in flour and batter by near infrared reflectance spectroscopy (NIRS)

Near infrared spectroscopy (NIRS) has been used as a valuable tool for quality control in the food industry. The aim of the present study was to investigate the possibility of developing a NIRS calibration for gluten determination in flour and batter, suitable for the analysis of gluten-free food products. Reflectance data was used for calibration based on modified partial least squares (MPLS) regression. Independent prediction equations were developed for flour and for batter. Spectral models using mean spectra of two scans (average spectra), were compared with those using the two individual spectral data. The best model obtained for flour was using the average spectral data (R 2 = 0.985; r 2 = 0.967) and for batter samples was using the individual spectral data (R 2 = 0.926; r 2 = 0.825). It is concluded that the application of NIRS methodology can predict accurately the concentration of gluten content in flours and batters, but it should not be considered as a reliable method for determining gluten contamination in gluten-free products. © 2012 Elsevier Ltd.