Effect of high pressure treatment on thermal and rheological properties of lentil flour slurry

Thermal characteristics of high pressure (HP) treated lentil flour dispersions were studied as function of pressure level (350–650 MPa) and moisture content (14–58 g per 100 g of flour). Differential scanning calorimeteric (DSC) measurement of pressure treated lentil dispersions indicated incomplete denaturation of lentil proteins. The protein dentauration temperature (Td) shifted with applied pressure and moisture content non-systematically. No starch gelatinization peak was detected during thermal scanning of lentil slurries (untreated or treated) irrespective of moisture content or heating rate. High pressure treatment of lentil dispersion significantly reduced the retrogradation behavior compared with that obtained from the thermally gelatinized sample. Dynamic rheological measurement indicated pressure treated lentil slurries exhibited a true viscoelastic fluid. Slurries gradually transformed from solid-like behavior to liquid-like behavior as function of moisture content and pressure level. Fourier transform infrared (FTIR) spectroscopy confirmed insignificant change in amide band of pressure treated slurry. This study has provided complementary information of pressure-induced structural changes on both the molecular and the sub-molecular level of lentil protein.