Hydrogel formulation based on galactomannan from residual spent coffee ground confers bioactivities and viscosifying properties in milkshake

The defatted residual spent coffee (RSC) was used for optimal recovery of 67.11% galactomannans by extraction using 1:10 w/v RSC:water at 80 & DEG;C/180 min followed by precipitation using 90% v/w ethanol. The obtained galactomannans (RSCGa) (MW- 274.67 kDa) showed antioxidant and prebiotic activity. A 3:5 ratio of RSCGa and kappa-carrageenan (xC) was used to prepare hydrogels (RSCGa-xC*) with CaCl2 (0.02 M) at 75 & DEG;C/pH 7.2. RSCGa improved the dynamic moduli of RSCGa-xC* (G & PRIME;, 8300 Pa and G & DPRIME;, 7800 Pa) compared to xC hydrogel. RSCGa-xC* showed DPPH, ABTS& PLUSMN; and FRAP activities of 553.23 & mu;g AAE/mg sample, 615.30 & mu;g AAE/mg sample, and 13.98 & mu;M FeSO4/mg sample, respectively, and prebiotic score of 30.89. The LCMS profiling of RSCGa-xC*, alike RSCGa, showed abundant phenolics. Adding 7.5% w/v of RSCGa-xC* in milkshake showed a desirable viscosity and good overall acceptability apart from the antioxidant and prebiotic activities. The present study outlines a sustainable approach for valorising RSC by developing a hydrogel that had dual functionality of technological and nutraceutical advantages which enhanced the quality of milkshake.

Automated summary

This study developed a sustainable approach for valorizing defatted residual spent coffee (RSC) by extracting galactomannans and preparing hydrogels with dual functionality of technological and nutraceutical advantages. The obtained galactomannans (RSCGa) showed antioxidant and prebiotic activities, and the hydrogel (RSCGa-xC*) exhibited desirable viscosity and good overall acceptability apart from its functional properties.