ABSTRACT
When lettuces (Lactuca sativa L.) grown for 30 days in hydroponic culture were treated with various concentrations of cyanocobalamin for 24 h, its content in their leaves increased significantly from nondetectable to 164.6 ± 74.7 ng/g fresh weight. This finding indicated that consumption of only two or three of these fresh leaves is sufficient to meet the Recommended Dietary Allowance for adults of 2.4 µg/day. Analyses using a cobalamin-dependent Escherichia coli 215 bioautogram and LC/ESI-MS/MS demonstrated that the cyanocobalamin absorbed from the nutrient solutions by the leaves did not alter any other compounds such as coenzymes and inactive corrinoids. Gel filtration indicated that most (86%) of the cyanocobalamin in the leaves was recovered in the free cyanocobalamin fractions. These results indicated that cyanocobalamin-enriched lettuce leaves would be an excellent source of free cyanocobalamin, particularly for strict vegetarians or elderly people with food-bound cobalamin malabsorption.
Subject(s)
Food, Fortified/analysis , Hydroponics , Lactuca/chemistry , Lactuca/growth & development , Vitamin B 12/analysis , Plant Leaves/chemistry , Plant Leaves/growth & development , Plant Leaves/metabolism , Recommended Dietary Allowances , Vitamin B 12/metabolismABSTRACT
This study determined the vitamin B12 content of six wild edible mushrooms which are consumed by European vegetarians. Zero or trace levels (0.01-0.09 µg/100 g dry weight) of vitamin B12 were determined in porcini mushrooms (Boletus spp.), parasol mushrooms (Macrolepiota procera), oyster mushrooms (Pleurotus ostreatus), and black morels (Morchella conica). By contrast, black trumpet (Craterellus cornucopioides) and golden chanterelle (Cantharellus cibarius) mushrooms contained considerable levels (1.09-2.65 µg/100 g dry weight) of vitamin B12. To determine whether C. cornucopioides or C. cibarius contained vitamin B12 or other corrinoid compounds that are inactive in humans, we purified a corrinoid compound using an immunoaffinity column and identified it as vitamin B12 based on LC/ESI-MS/MS chromatograms.
