Contents lists available at ScienceDirect LWT - Food Science and Technology journal homepage: www.elsevier.com/locate/lwt High uptake and inward diffusion of iron fortificant in ultrasonicated milled rice Aldrin P. Bonto a,d , Nichada Jearanaikoon c , Nese Sreenivasulu d , Drexel H. Camacho a,b,* a Chemistry Department, De La Salle University, 2401 Taft, Avenue, Manila, 0922, Philippines b Organic Materials and Interfaces Unit, CENSER, De La Salle University, 2401 Taft, Avenue, Manila, 0922, Philippines c Synchrotron Light Research Institute, Public Organization, Nakhon Ratchasima 30000, Thailand d Grain Quality and Nutrition Center, Strategic Innovation Platform, International Rice Research Institute, Los Baños, Philippines ARTICLE INFO Keywords: Rice Fortification Iron Sonication Micronutrient ABSTRACT Nutritional iron content in milled rice is generally lost as a result of milling due to removal of aleurone layer. Iron fortification in milled rice is recommended to regain the lost nutrients and address the malnutrition issues. This work investigates the uptake of iron and its diffusion into the kernel on ultrasonic-treated milled rice. Rice samples were subjected to ultrasonic waves resulting in the formation of microporous surfaces and the creation of fissures in the milled rice. Sonication followed by soaking in aqueous iron solution resulted in the uptake of 321 ± 13.43 mg of iron per kg of rice, a 28-fold increase compared to the endogenous iron content of milled rice with retention of 82.9% upon washing and cooking. Cross-section mapping (μ-XRF) of the concentration of the fortificant into the uncooked grains showed inward diffusion at different rates reaching into the kernel core. Results also show that sonication decreased the amount of water-soluble phosphorus in rice suggesting the removal of potentially anti-nutrient phytic acid. Textural analysis of ultrasonic-treated iron-fortified rice premix revealed favorable properties that can be advantageous for its consumer acceptability. 1. Introduction Micronutrient deficiencies approximately affect two billion people worldwide leading to dramatic health impact resulting in stunting, poor growth and significant implications for health and cognitive develop- ment. To address this problem, deliberate supplementation of essential micronutrients in the human diet can be carried out. However, for- tification, or nutritional enrichment of generally consumed food is seen as an effective mass approach to prevent malnutrition in a wide range of population. Food fortification with micronutrients has been re- cognized as an important intervention in public health programs for preventing and treating a deficiency of essential micronutrients in many developing countries. Different transnational and governmental re- search programs have been applied to alleviate malnutrition through food fortification of dairy products, cooking oil, and cereal flour (Preedy, Srirajaskanthan, & Patel, 2013). Among these food fortifica- tions, rice remains the most successful fortificant vehicles since it is consumed by two-thirds of the world's population. As an excellent food material for delivering micronutrients to a very large number of people, rice fortification is promoted by the Food and Agriculture Organization (FAO) to improve the daily intake of essential nutrients and to help in addressing the malnutrition and other health issues of the human po- pulation (FAO, 2004). In micronutrient malnutrition, iron (Fe) deficiency has been af- fecting 70–95% of Asia's population where rice is the staple diet. Daily Fe intake recommended is 13.7–20.5 mg per day (FAO 2001). The baseline availability of Fe in milled rice is 2 mg kg -1 (Bouis, Hotz, McClafferty, Meenakshi, & Pfeiffer, 2011), hence there is a need for an intervention of multiple strategies to address the problem. One of the most serious consequences of iron deficiency is anemia, which reduces work efficiency, learning ability, and spontaneous activity. Iron defi- ciency also impairs growth, slows development of children, and weakens immunity, especially in infants and young children, as well in pregnant women (WHO/FAO, 1998). Several methods have been in- vestigated in rice iron fortification. Foremost of which is the bioforti- fication of iron in rice through genetic approaches lead to increase the Fe content ranging between 7 and 11 mg kg -1 in different transgenic events (Ludwig and Slamet-Loedin, 2019; Masuda et al., 2012). How- ever, the tough regulations put in place for GMO strategies is the major barrier in gaining consumer traction limiting the acceptability of ge- netically engineered products. Biofortification through non-GMO pro- gress is very limited due to lack of genetic variability. Although https://doi.org/10.1016/j.lwt.2020.109459 Received 12 February 2020; Received in revised form 7 April 2020; Accepted 18 April 2020 * Corresponding author. Chemistry Department, De La Salle University, 2401 Taft, Avenue, Manila, 0922, Philippines. E-mail address: drexel.camacho@dlsu.edu.ph (D.H. Camacho). LWT - Food Science and Technology 128 (2020) 109459 Available online 22 April 2020 0023-6438/ © 2020 Elsevier Ltd. All rights reserved. T