Thermodynamic Properties of Ready-to-Puff Pressure Parboiled Preconditioned Brown Rice

摘要

Preconditioning of pressure parboiled brown rice was carried out at different salt concentrations (SC) 0–4% using a fluidized bed dryer at 75±3 °C to obtain pressure parboiled preconditioned brown rice (PBR). The isotherm data were obtained at different moisture contents (MC) 3–25% and temperatures (T) 20–30 °C. The thermodynamic properties (isosteric enthalpy, ΔHis; isosteric entropy, ΔSis; integral enthalpy, ΔHin and integral entropy, ΔSin) of ready-to-puff PBR were calculated using the Clausius–Calpeyron and Gibbs–Helmotz equations. The individual effect of SC and T on all the thermodynamic properties was observed to be highly significant (p<0.0001). Different categories of functions (exponential, logarithmic, rational, polynomial andpower) were used to explain the relationship between individual thermodynamic properties with MC. It was observed that among all the functions the polynomial and logarithmic equations are most suitable for differential properties and integral properties, respectively.