Aging kinetics of low amylose rice during storage at ambient and chilled temperatures

The objectives of this study were to monitor the changes in rice properties during aging and to compare kinetic parameters related to some of those changes. Paddy of three low amylose rice varieties was stored at ambient (30 ± 2ºC) and chilled (8 ± 2ºC) temperatures for 9 and 18 months, respectively. Aging led to a decrease in solid loss, peak viscosity, breakdown, and adhesiveness and an increase in head rice yield, minimum cooking time, water uptake, volume expansion, pasting temperature, final viscosity, through viscosity, setback, and hardness. Low temperature storage efficiently retarded those changes. Data of the time-dependent changes in hardness, adhesiveness, pasting temperature, peak viscosity, and breakdown of all samples stored at 30°C were fitted well with the first-order fractional conversion kinetic model (R2 = 0.77 – 0.98). Higher storage temperature resulted in greater rate constant (k; up to 9 times higher) of those changes.