Abstract
Edible mushrooms are an important source of various nutrients for vegetarians. However, vitamin B_<12> contents of various truffle and shoro fruiting bodies is unknown, and it is also unknown whether they contain vitamin B_<12> or the pseudovitamin B_<12>, which is biologically inactive in humans. We characterized and quantified vitamin B_<12> in the fruiting bodies of black and white truffles (Tuber spp.) and "shoro" (Rhizopogon rubescens) using a microbiological assay based on Lactobacillus delbrueckii subsp. lactis ATCC 7830. Bottled black truffle fruiting bodies contained approximately 4.5 μg of vitamin B_<12> per 100 g of wet weight, but the vitamin B_<12> contents of raw and frozen samples contained approximately 50% or less vitamin B_<12>. In addition, bottled white truffle and shoro fruiting bodies contained approximately 2.9 μg and 3.3 μg of vitamin B_<12> per 100 g of wet weight, respectively. The mean values (approximately 11.5 μg of vitamin B_<12> per 100 g dry weight) of these truffle fruiting bodies were higher than those reported for other edible mushroom fruiting bodies. Corrinoids were purified from the black and white truffles and shoro fruiting bodies and vitamin B_<12> was identified using liquid chromatography-electrospray ionization tandem mass spectrometry.
