Fortification of rice with folic acid using parboiling technique: Effect of parboiling conditions on nutrient uptake and physical characteristics of milled rice

Parboiling was used as a technique for folic acid fortification in brown rice. A range of parboiling conditions (i.e. 70 °C soaking for 1, 2 and 3 h with 0.15, 0.3, 0.6 and 1.2 g folic acid/300 g brown rice and milled for 0, 60 and 120 s) were studied to investigate the uptake of folic acid in the fortified rice. Approximately 20–300 μg folic acid/g was found in the fortified rice and an average of 90% of folic acid was retained in the washed and cooked fortified rice. The quality of the fortified rice was evaluated based on head rice yield (HRY), kernel dimensions and color. No significant change in HRY and grain dimensions were observed between raw and fortified rice, suggesting the economic value of rice will not be compromised with the fortification process and rice uniformity may likely be achieved after mixing with the untreated rice. Despite the inherent yellow color of folic acid, in comparison with parboiled rice, a significant difference in yellowness was exhibited only in rice fortified at 1.2 g folic acid/300 g brown, but not among those fortified at lower fortificant concentrations. The difference in lightness (ΔL∗) (between fortified rice and parboiled rice) was reduced as soaking duration increased.

► Parboiling is a feasible approach for folic acid fortification in rice.
► Head rice yield and grain dimension are maintained for fortified rice.
► Folic acid does not significantly impact on the yellowness color of rice.