Influence of Heat Treatment Prior to Fortification on Goitrogenic Compounds, Iodine Stability and Antioxidant Activity in Cauliflower

Iodine deficiency remains a global public health concern. Preliminary studies confirmed that cauliflower can serve as a carrier for iodine salts. However, the influence of its endogenous goitrogenic compounds (phenolic compounds and glucosinolates) on iodine utilisation is not fully understood. This study aimed to assess the potential for enhancing cauliflower’s effectiveness as an iodine carrier through various thermal pre-treatment methods, and to examine how these methods, along with the plant’s endogenous goitrogens, affect iodine stability. Cauliflower was cooked by steaming or boiling (covered or uncovered) and fortified with KI or KIO3. Iodine content, selected phenolic compounds (sinigrin, progoitrin, glucobrassicin, gluconapin, indole-3-carbinol) and antioxidant activity (ABTS●+, DPPH●) were analysed immediately after fortification and after 90 days of storage at 4, 21, or 40 °C under controlled humidity and darkness. The results showed that both the heat-treatment method and storage temperature significantly affected iodine retention and were associated with changes in goitrogenic compounds and antioxidant capacity. Cauliflower demonstrated favourable stability as a carrier of iodine, although phytochemical composition influenced fortification outcomes. These findings suggest that the initial heat treatment of cauliflower significantly affects its effectiveness as a matrix for iodine fortification, likely due to differences in the content of goitrogenic compounds.