Folate fortification of rice through parboiling: optimisation, rice quality, consumer acceptance and in-vitro relative bioaccessibility & absorption using Caco-2 cells

Parboiling has been examined in this thesis as the means to fortify rice with folic acid. The development of the fortification method was governed by four major aspects, namely, optimisation based on nutrient retention, rice quality, consumer acceptance and nutrient bioaccessibility and absorption. Multifactorial models were developed to describe folate retention. The optimal parboiling condition for the fortification purpose was soaking brown rice at 70 ◦C for 2 h. Fortified rice produced at 70 ◦C was further investigated for the rice quality examination, focussing on Head Rice Yield, kernel dimensions and colour. No significant change in Head Rice Yield and grain dimension was observed between raw and fortified rice, suggesting that 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 colour of folic acid, compared to parboiled rice, significant difference in yellowness was exhibited only in rice fortified at 1.2 gfolic acid/ 300 gbrown rice, but not among that fortified at lower concentrations. Visual and organoleptic acceptance of the fortified rice by consumers was examined. The appearance of uncooked rice (fortified at 1.2 gfolic acid/ 300 gbrown rice) prepared at 70 ◦C and soaked for 1 h resembled the commercial parboiled rice. An informed health claim on the fortified rice increased the consumers purchase intent which suggested that they welcomed the fortified product. Food familiarity (i.e. familiarity with parboiled rice) improved consumers purchase intent suggesting a higher chance of acceptance in the parboiled rice-consuming countries. The sensory acceptability of three cooked rice samples (rice soaked in 0.15 gfolic acid/ 300 gbrown rice at 70 ◦C for 1, 2 and 3 h and then mixed in with commercial white rice) was compared to the commercial white rice (ControlWhite). No significant difference was noted in liking attributes between the samples and ControlWhite. More than 50 % of the consumers were willing to purchase the samples. Their purchase intent increased after they were notified of the additional health benefits from the rice, they especially inclined to purchase the rice soaked for 2 and 3 h. Lastly, the bioaccessibility and absorption of folic acid in the fortified rice was assessed using in-vitro Caco-2 cell model. Fortified rice was more bioaccessible (91 %) than the aqueous folic acid control (81 %). As for the extent of absorption, no significant difference was observed between the transport results of fortified rice and folic acid control, suggesting that the added folic acid in the fortified rice could be absorbed as well as the control