Variation in Contents of Iodine Species in Kelp during Blanching-Salting Process

Abstract

In this study, the contents of four iodine forms, including iodide ion (I−), iodate (IO3−), mono-iodotyrosine (MIT) and diiodotyrosine (DIT), were determined in the blanching water, rinsing water, saline water and processed kelp to study the dissolution patterns of iodine forms during the blanching, rinsing and salting of kelp. The I− contents in fresh, blanched, primarily rinsed and secondarily rinsed kelp were 1 689.41–8 753.24 mg/kg, and the contents of IO3− ranged from 42.67 to 442.00 mg/kg. The contents of MIT and DIT ranged from 698.22 to 861.90 mg/kg and 123.97 to 158.67 mg/kg, respectively. During the blanching process, the dissolution rates of I−, MIT and DIT were the highest, which were (64.38 ± 2.99)%, (19.35 ± 0.97)% and (6.55 ± 0.53)%, respectively. With increasing kelp addition, the contents of I−, MIT and DIT in the blanching, rinsing and saline water first increased and then leveled off, and the content of IO3− in all waters showed a monotonously increasing trend. With increasing number of kelp rinsed, the dissolution rate of I− decreased first and then basically remained unchanged. Compared with fresh kelp, the dissolution rate of I− in the first rinsed kelp decreased by (80.72 ± 2.66)%, and iodine was released into water mainly in the form of I−, with the maximum release being recorded during the blanching process.

Keywords

• kelp; iodine species; blanching; rinsing; salting