Physicochemical, functional and ATR-FTIR molecular analysis of protein extracts derived from starchy pulses

An alkaline solubilisation and isoelectric point precipitation process were used to isolate proteins from broad bean, chickpea, lentil and white bean. The physicochemical, water solubility and foaming properties as well as their protein digestion characteristics of whole flours and its protein extracts were correlated with their molecular characteristics, analysed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The processing of pulses resulted in protein recoveries >= 50.12% and yields up to 30.26% for broad bean. The purity of the protein was from 68.27% to 86.58% for chickpea and broad bean, with invitro digestion values >= 80.59%. The protein extracts showed up to 0.85 mg g(-1) of phenolic compounds (gallic acid eq./100 g). The ATR-FTIR analysis of the extracts showed different proportions of alpha-helix and beta-sheet secondary structures of the amide II group. The analysis of the amide III group reflected inter- and intramolecular associations that could have influenced their emulsion and foam characteristics.