Effect of Ultrasound and Enzymatic Hydrolysis on the Physicochemical Properties of Neltuma Ruscifolia Seed Gum and Other Galactomannan Gums

Galactomannans are polysaccharides commonly extracted from the endosperm of various leguminous seeds, exhibiting variations in their man/gal ratio based on their botanical origin. These gums are highly valued for their biodegradability and excellent stability. However, their applications have been limited due to their high viscosity and molecular weight. In this study, enzymatic and ultrasound depolymerisation of galactomannans (guar gum, locust bean gum, and unconventional Neltuma ruscifolia seed gum) was carried out, resulting in hydrolysates, which were subsequently freeze-dried and characterised. The hydrolysis process leads to a decrease in viscosity and molecular weight, accompanied by a noticeable increase in polydispersity through enzymatic treatment. Thin-layer chromatography (TLC) analysis indicates the generation of at least eight-membered subunits. Fourier-transform infrared (FT-IR) spectroscopy analysis demonstrates no significant changes in functional groups following ultrasound hydrolysis. Furthermore, in agreement with TLC results, enzymatic hydrolysates display partial reactivity towards non-enzymatic browning (NEB), yielding mostly intermediate products with limited browning development. This study diversifies potential applications of these gums in different industries. Graphical Abstract