Reduction of off-flavours and the impact on the functionalities of lentil protein isolate by acetone, ethanol, and isopropanol treatments

The changes of flavour profiles in lentil protein isolate (LPI) in response to organic solvent treatments (acetone, ethanol, and isopropanol; 35-95% v/v), and the resulting impacts on the isolate colour and physicochemical and functional attributes were investigated. The major constituents of volatile compounds were aldehydes (similar to 46.59%) and (E,E)-3,5-octadien-2-one (similar to 31.79%) in the untreated LPI. Acetone treatment greatly raised ketones by similar to 79.59%. In contrast, ethanol and isopropanol, except at 95% (v/v), significantly lowered total volatile compounds and had higher protein contents (similar to 84.55%) than the others (similar to 76.98%); surface charge, surface hydrophobicity, solubility and emulsion stability of these LPIs were examined. LPIs obtained from 75% (v/v) ethanol and isopropanol treatments showed slightly lower solubility but improved surface hydrophobicity to produce emulsions with a similar stability as compared with the untreated LPI. Overall, ethanol and isopropanol treatments (75% v/v) produced high quality off-flavour-reduced LPIs which may be used in various food systems.