Influence of the extraction time on macromolecular parameters of galactomannans

• Galactomannan macromolecular parameters are not affected by the extraction time.
• Aggregates of galactomannans are disassembled in solution.
• Viscometer provides a more reliable galactomannan L’p than light scattering.

This study evaluated the aqueous extraction of galactomannans from the seeds of Mimosa scabrella (GM), Stryphnodendron adstringens (GS) and Schizolobium parahybae (GG) for 1, 2, 3, 4, 6, 24 and 48 h. The efficiency of extraction processes was assessed in terms of yield, carbohydrate and protein content. The extraction process, as well as the source of the galactomananns generated molecules with differences in molar mass, viscosity and rigidity analyzed by HPSEC-MALLS/RI/VIS. The extraction time results for each species, based on minimum extraction time and HPSEC-MALLS/RI/VIS results, were 4 h (GM4 h), 6 h (GS6 h) and 2 h (GG2 h) for GM, GS and GG, respectively. In most cases, the apparent persistence length, as determined by viscometry, indicated that aggregates remained in galactomannans after centrifugation and filtration. Results suggest an effective extraction time for each plant source of galactomannan based on its performance and its macromolecular behavior in solution.