Results, Discussion and Conclusion
From particle size distribution, the highest portion of rice flour was on the 180 μm particle size, amounting to 17.4 % whereas the smallest particle size portion passed through the 75 μm sieve was about 12%. Table 1 showed chemical and physical properties of each flour fraction. As particle size reduced, the protein content of the flour seemed to decrease whereas ash content showed opposite results. However, the amylose content of all flour fractions was similar ranging between 30.8 and 32.5%. For WAI and WSI, it was clear that the smaller particle size gave the higher value of these two properties. The smaller particle size fraction exhibited whiter color as L-value increased whereas yellow color was potentially reduced as b-value decreased.
Table 1. Chemical compositions, water absorption index, water solubility index and color value of dry-milled rice flour from different fractions.