Contents of vitamin B9 (folate) and B12 (cobalamins) in commonly consumed seafood menus in Korea

Purpose: A total of 39 seafood menus were prepared according to the Korean standard recipe, and analyzed for vitamin B9 (folate) and B12 (cobalamins) contents, using validated applied analytical methods. The menus included Guk/Tang/Jjigae (boiled or stewed dishes, n = 10), Bokkeum (stir-fried dishes, n = 10), Jjim/Jorim (braised or steamed dishes, n = 7), Gui (baked or grilled dishes, n = 7), Twigim (deep-fried dishes, n = 2) and Muchim (dried or blanchedseasoned dishes, n = 3). Methods: The contents of vitamin B9 and B12 in all food samples were determined by the trienzyme extraction-Lactobacillus casei and immunoaffinity-high-performance liquid chromatography/photodiode array detection methods. Analytical quality control was performed in order to assure reliability of the analysis. Results: Accuracy (97.4–100.6% recoveries) and precision (< 6% relative standard deviations for repeatability and reproducibility) of vitamin B9 and B12 analyses were determined to be excellent. The vitamin B9 and B12 contents of the 39 seafood menus evaluated, varied in the range of 1.83–523.08 μg/100 g and 0.11–38.30 μg/100 g, respectively, depending on the ingredients and cooking methods. The vitamin B9 content was highest in Jomi-gim (523.08 μg/100 g), followed by Geonsaeu-bokkeum (128.34 μg/100 g) and Janmyeolchi-bokkeum (121.53 μg/100 g). Vitamin B12 was detected in all seafood menus, with highest level obtained in Kkomack-jjim (41.58 μg/100 g). The seaweed dish was found to have high levels of both vitamin B9 and B12. All assays were performed under strict quality control. Conclusion: Guk and Tang menus, which contain a large amount of water, were relatively lower in the vitamin B9 and B12 contents than the other menus. Bokkeum menus containing various vegetables were high in the vitamin B9 content, but the vitamin B12 content was dependent on the type of seafood used in the menu.