Changes in structure and physicochemical properties of Sophora japonica f. pendula galactomannan in late growth stage

Abstract

Galactomannan (GM) has been widely applied in food and other fields due to its appealing physicochemical properties. In this work, considering the changes in structural and physicochemical properties of Sophora japonica f. pendula (SJ-GM) with very high mannose to galactose (M/G) ratio in the late deposition stage, extensive exploration is conducted. The core of structural change is the change of M/G ratio (4.94-5.68), which is caused by the loss of galactose side residues modulated by α-d-galactosidase during seed maturation. Afterwards, the more compact conformation, the higher molecular weight, the increased hydrophobicity, and the greater solution viscosity of SJ-GM can be caused. Notably, the gel strength of SJ-GM with the highest M/G surpasses other GMs, including fenugreek gum (M/G = 1.20), guar gum (M/G = 1.80), Gleditsia microphylla gum (M/G = 2.77), and LBG (M/G = 4.00). Finally, SJ-GM is proven to be an attractive alternative to other GMs.

Keywords: Galactomannan (PubChem CID: 439336); Gel strength; Guar gum (PubChem SID: 472386365); Late deposition stage; Locust bean gum (PubChem CID: 333186); P-nitrophenyl-α-d-galactopyranoside (PubChem CID: 82000); Ratio of mannose to galactose; Sodium 2,2-dimethylsilapentane-5-sulphonate (PubChem CID: 5167273); Sophora japonica f. pendula galactomannan; Xanthan gum (PubChem CID: 47932); α-d-Galactosidase; α-d-Galactosidase (PubChem SID: 472420644).