Iodine Biofortification of Four Brassica Genotypes is Effective Already at Low Rates of Potassium Iodate

Abstract

The use of iodine-biofortified vegetables may be a health alternative instead of iodine-biofortified salt for preventing iodine (I) deficiency and related human disorders. In this study, four Brassica genotypes (broccoli raab, curly kale, mizuna, red mustard) were hydroponically grown with three I-IO3− rates (0, 0.75 and 1.5 mg/L) to produce iodine-biofortified vegetables. Crop performances and quality traits were analyzed; iodine content was measured on raw, boiled, and steamed vegetables. The highest I rate generally increased I content in all Brassica genotypes, without plants toxicity effects in terms of reduced growth or morphological symptoms. After 21 day-iodine biofortification, the highest I content (49.5 µg/100 g Fresh Weight (FW)) was reached in broccoli raab shoots, while after 43 day-iodine biofortification, genotype differences were flattened and the highest I content (66 µg/100 g FW, on average) was obtained using 1.5 mg I-IO3/L. Nitrate content (ranging from 1800 to 4575 mg/kg FW) was generally higher with 0.75 mg I-IO3/L, although it depended on genotypes. Generally, boiling reduced iodine content, while steaming increased or left it unchanged, depending on genotypes. Applying low levels of I proved to be suitable, since it could contribute to the partial intake of the recommended dose of 150 µg/day: A serving size of 100 g may supply on average 24% of the recommended dose. Cooking method should be chosen in order to preserve and/or enhance the final I amount.

Agronomic iodine biofortification of leafy vegetables grown in Vertisols, Oxisols and Alfisols

“…However, in this study the I U is affected by differences in biomass production for these vegetables which was in the sequence of Vertisol > Alfisol > Oxisol (Table 2 ). The I C data confirm the findings of Dai et al ( 2004 ) and Gonnella et al ( 2019 ) that green vegetable species show variations in I C and efficacy of translocation within the plant.…”

Mineral Biofortification of Vegetables as a Tool to Improve Human Diet

“…Low doses of I, such as 0.25 mg L −1 (KI) or 0.50 mg L −1 (KIO 3 ) in the nutrient solution are enough to achieve around 7 mg kg −1 DW of I in strawberry fruits, compared to 0 in the control, improving plant growth too [ 79 ]. Analogous results were observed in several leafy vegetables (e.g., broccoli raab, curly kale, mizuna or red mustard) when submitted to low doses of iodine (0.75 mg L −1 , 5.9 µM KIO 3 ) through fertigation, showing an increase ranging from 390 to 471 µg kg −1 FW [ 80 ]. However, high I levels (50 mg L −1 ) in the nutrient solution, proved to increase the I content in carrot up to toxic amounts for humans (9 mg kg −1 FW) showing also phytotoxic effects on plants [ 76 ].…”

Living Mulch and Organic Fertilization to Improve Weed Management, Yield and Quality of Broccoli Raab in Organic Farming

“…For anion content determination, the ion exchange chromatography (Dionex DX120, Dionex Corporation, Sunnyvale, CA, USA) with a conductivity detector was performed as reported by Gonnella et al [28]. Nitrate, Cl, SO 4 , and H 2 PO 4 and oxalate contents were determined in 0.5 g of dried sample using an IonPac AG14 precolumn and an IonPac AS14 separation column (Dionex Corporation).…”