Investigation of fissure formation during the drying and post-drying of Japonica aromatic rice
2008
Hashemi, J. (University of Agricultural and Natural Resource Sciences, Sari (Iran). Dept. of Agricultural Machinery Engineering) | Shimizu, N. (University of Tsukuba, Ibaraki (Japan). Graduate School of Life and Environmental Sciences)
Fissure formation Mechanism of Kaori aromatic rice under different drying and post-drying conditions was investigated by differential scanning calorimetry (DSC). Samples dried at 50 degree C and 60 degree C to standard and low final moisture content (FMC), the maximum fissuring rate occurred after approximately 12 h. Increasing difference between storage and drying air temperatures increased fissured kernels. The mean value of glass transition temperatures (Tg) showed that to achieve a FMC up to 12% and 9%, the temperature must be below 45 degree C and 52 degree C, respectively. Drying temperatures higher than these are likely to produce a high proportion of fissured kernels. The DSC diagram indicated that at the onset of drying, kernels state changed from a glassy to a rubbery and during the drying it returned to the glassy state. Therefore fissured kernels at low FMC was approximately 10% more than standard FMC. It can be concluded that a high drying temperature might have a more negative effect than low FMC on the structure of Kaori aromatic rice and leads to deterioration in its quality.
显示更多 [+] 显示较少 [-]