EFFECTS OF HIGH-PRESSURE TREATMENT ON FUNCTIONAL, RHEOLOGICAL, THERMAL AND STRUCTURAL PROPERTIES OF THAI JASMINE RICE FLOUR DISPERSION

摘要

Effect of high-pressure (300-600 MPa) and flour to water (F/W) ratio (1:1-1:4) on functional, rheological, thermal and structural properties of Thai Jasmine rice flour were investigated. Water holding capacity and water solubility index of high-pressure-treated rice samples increased linearly with pressure intensity. Pressure treatment significantly influenced the particle size distribution of flour. Thermal transitions and the mechanical property of pressure-treated samples were measured by DSC and rheometry, respectively. Starch gelatinization of rice flour is affected by both applied pressure and F/W ratio. The mechanical rigidity G0 of rice flour decreased with increasing F/W ratio and increased with the pressure level. The peak viscosity, hot paste viscosity and final viscosity decreased significantly with increasing pressure intensity. Fourier-transform infrared (FTIR) spectroscopy showed changes in the secondary structure of rice proteins and the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed changes in the protein subunits that occurred after the pressure treatment.