Background: The galactomannans are water-soluble carbohydrates widely used in the
food, pharmaceutical, biomedical, cosmetic, textile and paper industries. Recently, a need for an alternative
industrial source of galactomannans has arisen; one possible source is Honey locust
(Gleditsia triacanthos), which is abundant in Algeria.
Objective: The main objective of this study was to determine the physicochemical and rheological
properties of Water-Soluble Galactomannan (WSG) purified from the seeds of Algerian Honey locust
(Gleditsia triacanthos L.).
Methods: The galactomannan was purified from the seeds of Gleditsia triacanthos and was structurally
characterized by chromatographic (HPAEC, HPSEC-RID-MALLS) and spectroscopic (FT-IR,
1H, 13C NMR) methods.
Results: The Honey locust seed contains a high level of WSG (yield, 10%), and the molecular
weight of its WSG was approximately 871.9 kDa. A highly viscous solution was obtained and had
an intrinsic viscosity [η] of 7.14-7.25 dL/g and an optical activity [α]D of +38.7°. Chromatographic
and spectroscopic analyses indicated the presence of β-D-mannopyranose and α-D-galactopyranose
in the heteropolysaccharide at a molar ratio of 2.86:1. The linear backbone of its macromolecule has
a central core composed of 4-linked β-mannose units, with branches of galactose, linked to the carbohydrate
core through α(1-6) linkage.
Conclusion: These results lead to the conclusion that galactomannan presents the desirable physicochemical
characteristics suitable for applications in the pharmaceutical, cosmetic and food industries.