Comparison of the water-soluble carbohydrate composition and fructan structures of Agave tequilana plants of different ages

The composition of water-soluble carbohydrates from Agave tequilana plants of 2, 4 and 61/2 years were compared by HPLC, HPAEC-PAD, MALDI-TOF-MS and GC-MS. The plants of 2 years exhibited the highest levels of free monosaccharide and low molecular weight fructans (DP 3-DP 6) with potential application as prebiotics. A maximum of fructan polymerisation was achieved at 4 years with mean DP from 3 to 30, then it was decreased at 61/2 years with mean DP from 4 to 24. The linkage analysis showed an increase and decrease in the branching degree from 2 to 61/2 years with a maximum at 4 years, correlated to changes in t-beta-D-Fruf linkages with increased and decreased synthesis of (2 -> 1) and (2 -> 6)-beta-D-Fruf as well as 1,6-di-beta-D-Fruf linkages. (C) 2010 Elsevier Ltd. All rights reserved.