Impact of high pressure treatment on functional, rheological, pasting, and structural properties of lentil starch dispersions

Lentil starch (LS) dispersions (flour to water 1:4 w/w) were subjected to high pressure (HP) treatment at 0.1, 400, 500 and 600 MPa for 10 min, followed by evaluation on the functional, particle size, rheological, pasting, and structural properties of post-process samples. Water holding capacity of pressurized starch increased with the pressure intensity due to increase in damaged starch. The amount of resistant starch increased from 5 to 6.8% after pressure treatment at 600 MPa. An increase in starch granule particle size (196-207 mu m) was obvious after HP treatment. The lentil starch was completely gelatinized after pressure treatment at 600 MPa for 10 min as evidenced from differential scanning calorimetry, rheometry, X-ray diffraction (XRD) and scanning electron microscopy observation. The elastic modulus, G' of lentil starch gel was less frequency dependent, and higher in magnitude at high pressure (>500 MPa) than at lower pressure range (<= 400 MPa). XRD analysis revealed the disappearance of two diffraction peak intensities at 14.86 degrees and 22.82 degrees at 600 MPa for 10 min, which confirms the transformation of crystalline to amorphous region of lentil starch. Pasting properties were significantly influenced by the pressure treatment especially at 600 MPa, resulting in a considerable decrease in peak viscosity, breakdown and final viscosity, and an increase in peak time. It can be inferred that the functional properties of pressure treated LS are mainly based on the structural destruction of granules. (C) 2016 Elsevier Ltd. All rights reserved.