Ultrasonic wave-assisted surface modification of milled rice and its vitamin B uptake capacity: A new and efficient method for rice fortification

Rice is an important staple food that provides dietary energy supply to almost half of the world\u27s population. However, milling process is applied to improve many properties of rice often remove most of its nutritional contents. Rice fortification is therefore sought to improve the daily intake of essential nutrients and address the malnutrition and other health issues of the vast majority of the human population. This study explore the morphological changes on the outer endosperm of uncooked milled rice under sonication for better understanding of its ultrastructure and to allow adsorption of vitamins on the porous surface of the grain. To observe the morphological changes of rice, rice varieties (TH82, NSIC 222, IRC10 and Malagkit) were sonicated at varying sonication time with soication frequency maintained at 53 kHz. The sonicated rice varieties were then soaked in vitamin solution (thiamine B1, pantothenic acid B5 and pyridoxine B6) to assess the uptake capacity compared to non-sonicated rice. SEM results reveal the effects of sonication on the rice surface which cause micropore formation, cell wall exposure, and scattering of starch granules. On vitamin fortification, HPLC results show higher vitamin uptake of sonicated rice compared to non-sonicated rice (p \u3c 0.05). The adsorption parameters show that pantothenic acid exhibits heterogeneous binding on the sonicated rice surface. Retention of thiamine in fortified sonicated rice was significantly high (93.19 %) after cooking at 125 oC. Further fortification using fat-soluble vitamins and essential minerals (such as Fe and Zn) are recommended