Impact of pin-to-plate cold plasma depolymerization on the gelation and functional attributes of guar galactomannan

The present study aimed to investigate the impact of pin-to-plate cold plasma on the gelation and functional attributes of guar seed galactomannan. The guar galactomannan was subjected to 170 and 230 V treatment for 30 and 60 min and investigated for the gel characteristics and functional properties. The cold plasma treatment incurred galactomannan chain depolymerization with a reduction in the degree of polymerization (DP) ranging from 7.33% to 48.99%. The water contact angle (WCA) reduced from 110.93 degrees to 95.54 degrees, thus increasing the hydration capacity (36.73-45.90 g/g). These mechanisms diminish the gel viscosity (from 798. 227 cP of UT to 334.65 cP at 230-60) and the viscoelastic moduli (G'and G") indicating the low strength of gels from plasma-treated galactomannan (PT-GG). This further influenced the least gelation concentration, foam capacity, and foam stability. However, the critical strain (from 11.83% [UT] to 41% [230-60]), cross-over frequency (from 3.39 Hz [UT] to 15.3 Hz [230-60]), and degradation activation energy (from 18.445 kJ/mol [UT] to 21.721 kJ/mol [230-60]) of the PT-GG were increased (from 18.445 kJ/mol [UT] to 21.721 kJ/mol [230-60]) signifying the increased stability of gels by intramolecular and electrostatic forces. Thus, the cold plasma-induced depolymerization and hydrophilic modification of galactomannan influence the gelation and functional attributes which widen the potential applications of the hydrocolloid. Practical Applications Depolymerized guar gum is industrially known for its specific applications such as low-viscosity source of dietary fiber, stabilizers, complex forming, and encapsulating agents. This study shows the potential of cold plasma processing as an eco-friendly sustainable technology for producing depolymerized guar gum which can be applied as a source of fiber in enteral feed formulations, stabilizers in low viscous spreads and sauces, and also in thermo-reversible gel networks due to its thermal gel transition attributes.