Retention of iodine in fortified parboiled rice and its pasting characteristics during storage

Abstract

Iodine fortification, as potassium iodide (KI) or potassium iodate (KIO3), in parboiled milled rice was investigated. The fortified parboiled milled rice (9-10% moisture content) contained 11.6 × 10 -2 mol KI per 100-g salt or 9×10-2 mol KIO 3 per 100-g salt. The iodine-fortified parboiled milled rice after dialysis retained 80.50-84.87% iodine, while the milled rice retained 97-100% iodine in the samples. Test on in vitro starch digestion showed that most iodine was released within 15 min of starch digestion. The iodine-fortified and nonfortified parboiled milled rice showed significant higher pasting temperature, peak time and setback viscosity than normal milled rice. After storage for 5 months, iodine content in fortified parboiled milled rice decreased significantly (P ≤ 0.01), while iodine content in milled rice did not change during storage. For the rice stored at ambient temperature, the rapid visco-analyzer amylograph viscosity (peak viscosity, trough viscosity and final viscosity) increased during the first 2 months and decreased during storage. Iodine did not affect these attributes of parboiled milled rice. © 2007, Blackwell Publishing.