Polysaccharide extraction from sugarcane leaves: combined effects of different cellulolytic pretreatment and extraction methods

Abstract

This research was conducted to determine the combined effects of different cellulolytic pretreatments (cellulase vs. mixed enzymes) and extraction methods (water vs. deep eutectic solvent, DES) on the yield, chemical and functional properties of polysaccharide (PS) from sugarcane leaves (SCLs). The DESs used were choline chloride-1,4-butanediol (DESB) and choline chloride-urea (DESU). The SCLs were initially enzyme-pretreated, followed by extraction using water and DES respectively. The produced crude polysaccharide extracts (CPSs) were characterized via FTIR, total phenolics, DPPH free radical scavenging activity and in vitro simulated gastrointestinal analysis. The results indicated that cellulolytic pretreatment improved the PS yield by 14–16%, but reduced the solubility, DPPH activity and gastrointestinal digestibility of CPS. DES-CPSs possessed higher solubility and DPPH activity than water-CPSs. FTIR analysis unveiled that lignin–carbohydrate-complex was likely the component that restricted the solubility and probably the digestibility of water-CPSs. This study concluded that pretreatment and extraction procedures distinctively affected the chemical characteristics, and subsequently the functional properties of CPS.