Novel use of sugarcane leaf polysaccharide in -carrageenan blend hydrogel

Sugarcane leaves are the abundant crop residues on the field after sugarcane harvesting. This study was designed to investigate the effect of sugarcane leaf polysaccharide on the chemical, physicochemical, and bioactive characteristics of kappa-carrageenan blend hydrogel. Initially, the polysaccharide was extracted using hot water and alkaline peroxide, respectively, to produce water-extracted polysaccharide (WP) and alkaline peroxide-extracted polysaccharide (AP). Then, the chemical (soluble polysaccharide, phenolic content (TPC), FTIR) and bioactive (alpha-amylase inhibition (AI) and albumin denaturation inhibition (AD) activities) characteristics of WP and AP were determined. Next, kappa-carrageenan blend hydrogel was prepared by incorporating 1%(w/v) WP and AP separately into 2% (w/v) kappa-carrageenan. The gel strength, swelling index, FTIR, DSC, TGA, and post-digestion AI and AD of the hydrogels were determined. Results unveiled that WP contained higher soluble polysaccharide, TPC, AI, and AD activity than AP. However, AP was superior to WP in improving the gel strength and stability of hydrogel. AP hydrogel had the highest gel strength (754.0 +/- 3.5 g), swelling index (0.030 +/- 0.006), and post-digestion AD activity (78.1 +/- 3.3%). This pioneer study provides new insight into the novel use of sugarcane leaf polysaccharide in bioactive kappa-carrageenan blend hydrogel preparation. The bioactive blend hydrogel is expected to be an ideal encapsulating polymer to deliver bioactive ingredients in functional foods.