Solubility and crystal structure of N-(1-deoxy-β-D-fructopyranos-1-yl)-L-histidine monohydrate ('D-fructose-L-histidine')

Within a set of food-related Amadori compounds, crystalline N-(1-deoxy-beta-D-fructopyranos-1-yl)-L-histidine monohydrate (Fru-L-His x H(2)O) has an unusually low solubility in water, which we determined as 0.21 g/100 g at 25 degrees C. The majority of the other fructose-amino acid conjugates have solubilities exceeding 100 g/100 g in water at this temperature. We report the crystal structure data on Fru-L-His x H(2)O. The conformation of the carbohydrate is the normal (2)C(5) pyranose chair. Bond lengths and valence angles compare well with the average values from a number of pyranose structures. All hydroxyl and carboxyl oxygen atoms, all nitrogen atoms and the water molecule are involved in an extensive hydrogen bonding, which forms a network of infinite chains with small antidromic rings. (c) 2006 Elsevier Ltd. All rights reserved.