Physical characteristics of parboiled Korean glutinous rice (Olbyeossal) using a modified method

Abstract

A modified parboiling method was developed to parboil Korean glutinous rice and the physical characteristics of partially milled parboiled rice (PMPR) were investigated before and after cooking. The modified parboiling method involved tumbling to replace soaking the rice grains, tempering the wet grains, and retorting and drying were applied to prepare the PMPR. The conventional parboiling method included soaking at room temperature for 24 h, steaming, and drying the rice. PMPR made by the conventional method was prepared as a control. The modified parboiling method successfully produced PMPR with a higher hardness and thousand-grain weight by taking less processing time and less energy for soaking, which resulted in higher milled rice yield and head rice yield. However, no significant difference was observed in the PMPR bulk density. Rice kernel size tended to be longer and less thick due to parboiling. The color of the PMPR tended to be darker, as higher temperature was applied for processing. However, the color of the PMPR after cooking was lighter than that of PMPR before cooking. Cook-modified PMPR was as hard as cooked conventional PMPR but was less sticky compared to that of conventional cooked PMPR.