Determination of total protein and wet gluten in wheat flour by Fourier transform infrared photoacoustic spectroscopy with multivariate analysis

•FTIR-PAS was used for determination of total protein and wet gluten in wheat flour.•PLSR models for the acceptable prediction of TP and WG in wheat flour.•Effective wavelengths were selected by successive projections algorithm.•Reliability of constructed models was demonstrated by external validation.