EFFECT OF SOME STORAGE CONDITIONS ON THE PHYSICAL AND TECHNOLOGICAL PROPRIETIES OF RAW, PARBOILED AND QUICK COOKING RICE

Two varieties of Egyptian rice (Oryza sativa L.) namely Sakha 101 (Japonica) and Giza 182 (Indica) were employed in this study. Rice grains were stored for 9 months in three types of bags (polyethylene, polyethylene plus carton and polystyrene cup) at room temperature. The work to be described here was performed to figure out the best materials raw, parboiled and for packaging quick cooking rice grains in order to keep the physical and technological properties of the aforementioned rice. The results of this study can be summarized as follows: the physical properties of brown and white rice were varied from one variety to another. The water uptake and sedimentation values of brown, white and quick cooking of both raw and parboiled rice at 77C and 82C were varied according to of the tested rice varieties. In general, quick cooking white rice of Sakha 101 variety had the highest values of water uptake at both 77C and 82C as compared with those found in the other samples. On contrary, sedimentation value at 77C and 82C was decreased as affected by the previous mentioned conditions. Furthermore, the quick cooking white rice of the two tested varieties (Sakha 101 and Giza 182) had the highest values of alkali spreading values compared to the other rice samples. Generally, alkalispreading values decreased after subjecting the two mentioned rice varieties to parboiling process. In addition, the alkali spreading values remain, without significant changes as a results of using different packaging materials or storage period. Quick cooking parboiled brown rice of Giza 182 variety had the lowest gel consistency in comparing to the other rice samples. However, parboiling and storage for 9 months at 25 + 2C led to decrease in the viscosity of rice flour. Dealing with data presented in this study it can be concluded that storage of rice grains in polyethylene plus carton at room temperature was superior compared to those of polyethylene ad polystyrene cup in terms of maintaining storage stability, which in turn play an active role for improving the export of Egyptian rice over-seas, hence, increase the national income and finally develop the Egyptian economy.