A Study of Rice Parboiling Methods for Developing Countries

ABSTRACT A laboratory study was conducted to evaluate the existing traditional methods of parboiling in tropical Africa and recommend improvements for developing countries. Effects of parboiling method, rice variety, soaking treatment, and drying treatment on rice quality were evaluated. Traditional parboiling with steaming under pressure contributed to a higher head yield, more grain deformity, less white portion grains, and darker color than two parboiling methods with steaming under atmospheric pressure. Location of rice in the parboiling container influenced the quality and yield, resulting in a non-uniform product. Medium grain rice produced more desirable characteristics than long grain. Soaking before steaming of dry rice produced more desirable rice than direct steaming of naturally high moisture rice. Combination of infrared and shade drying produced higher head yield than only infrared drying. This combination gave similar head yields to two-pass mechanical drying with a modern parboiling method.