Physicochemical properties of mirchal glutinous rice flour based on soaking time

Abstract

The physicochemical and structural characteristics of highyield, tongil type mirchal glutinous rice, Milyang 328 (hereafter referred to as mirchal ), were compared to those of a set of well-characterized glutinous rice varieties i.e., baegokchal, dongjinchal, and sinseonchal. The results revealed that mirchal exhibited the highest crude protein content (8.47%), water binding capacity (209.00%), and swelling power (55.82 g/g) under long term soaking. Analysis under identical conditions revealed that mirchal rice flour presented the minimum mean and median particle diameters of 50.54 μm and 22.72 μm, respectively, among the tested varieties. Furthermore, the particle diameter and onset temperature (T o , 57.15℃) under these conditions were significantly lower than those under other conditions. The crystalline fraction of glutinous rice flour exhibited an A-type structure, irrespective of the soaking time. Mirchal exhibited the highest breakdown viscosity of 1,416.0 cP under short term soaking. The branch chain length distribution of the amylopectin A chain in the glutinous rice flours was arranged in the following sequence: baegokchal (30.82%) > mirchal (29.59%) > dongjinchal (28.74%) > sinseonchal (27.10%). The length distribution of the B1 chain in the glutious rice flours was arranged in the following sequence: dongjinchal (47.85%) > mirchal (47.17%) > baegokchal (45.83%) > sinseonchal (44.47%). Thus, this study revealed that mirchal possessed optimal processing characteristics owing to its high swelling power and excellent physicochemical properties, therby facilitating its application in the synthesis of yukwa and food processing materials.