51. Parboiling 3
- INDEX -
Points Concerning Quality and Appropriate Conditions
Selection of paddy
Soaking condition
Steaming conditions
Drying conditions
Points Concerning Quality and Appropriate Conditions
The characteristic quality of parboiled rice is summarized as follows: Hardened rice grains due to gelatinization of starch induced by hydrothermic process, off-flavor, and change of color.
These points have positive and negative effects on the value of parboiled rice as a commodity.
They are not induced by a single process but are formed by the interactive effects of two or more processes.
Therefore, it is never easy to give a product only the positive characteristics selectively.
Selection of paddy
As described above, the variety and quality of paddy affect quality. To obtain uniform products, it is necessary to have a uniform variety of paddy. The paddy should contain not so much dusty impurities and not to be contaminated with fungi etc. Contamination with dust might interrupt the flow of hot water supplied from the upper part of the tank in the hot water soaking process, resulting in retarded water absorption. Paddy contaminated with fungi etc. accelerate decomposition and fermentation during the cold soaking process, causing an off-flavor and discoloring.
In general, dried paddy is used in developing countries. When combine harvesters are distributed and fresh harvesting is performed in the optimal harvesting period, the soaking process can be shortened as with the pressure parboiled method. The soaking time can be half the conventional time when fresh rice is used. The product obtained is confirmed to have similar merits to the conventional ones.