Moreover, the residual sulfite content in parboiled grains was also evaluated. The lowest concentration of 0.2% sodium bisulfite was able to significantly (p < 0.05) promote a whiter colour, a decrease in the percentage of stained grains, and an increase in the percentage of completely gelatinized grains in the parboiled rice, compared to rice without sodium bisulfite treatment. However, the use of sodium bisulfite significantly (p < 0.05) reduced the thiamine content, which is considered a risk associated with the treatment.