1992 Volume 18 Issue 4 Pages 155-161
A storage examination of parboiled rice made from brown rice (Japonica) was conducted as well as an examination on how storage temperature, packaged materials and disoxidants effected the lipid change, the texture of the cooked rice and the gelatinization degree of the parboiled rice compared to the milled rice.
1) The moisture of the parboiled rice and the milled rice barely changed in storage at 4°C, regardless of the packaged materials. In storage at 37°C, the moisture of both samples had not changed when they used vapor deposition of aluminum film packages. However, when the polyethylene film packages were used, the moisture decrease about 23% in six months.
2) As for the lipid change of the parboiled rice and the milled rice during storage, peroxide value and carbonyl value of both greatly increased in storage at 37t. But at 4°C, the change was small and when using deoxidation the change was completely controlled. In the parboiled rice, acid value did not increase during storage.
3) From the results of the measurements of the texture of the cooked stored rice, in 37°C, the hardness of the parboiled rice increased and the cohesiveness and adhesiveness decreased as time passed. These changes were greater than the milled rice which was stored in the same temperature. However, when the parboiled rice was stored in 4°C, the texture of the cooked rice did not change, nor did not that of the milled rice.
4) As for the gelatinization degree of the cooked rice both the parboiled rice and the milled rice decreased by storage. However, the tendency to decrease was greater in the parboiled rice. The effect of the storage temperature and the packaged material on the gelatinization degree was small.
