Structure and chain conformation characterization of arabinoglucan from by-product of peanut oil processing

Abstract A neutral polysaccharide (NPP) from peanut sediment of aqueous extraction process was purified via anion-exchange and gel-filtration chromatography. The weight-average molecular weight and polydispersity index were 3.36 × 104 Da and 1.06. Composition of glucose (82.66%, molar percentage) and arabinose (17.34%) suggested an arabinoglucan structure. Multiple medium-length chains consisting of many 1,4-linked α-Glcp and a few 1,5-linked α-Araf maintained the main chain structure. The backbone was substituted at O-6 and O-3 positions, attached by side chains consisting of two to six α-Glcp and terminated with Araf and Glcp. Degree of branching was 42.50%. Aggregates formed in NPP aqueous solution. They were eliminated by DMSO combining with sonication. Consequently, the average radius of gyration (Rg), hydrodynamic radius (Rh), and Rg/Rh ratio were 17.0 nm, 5.8 nm and 2.93, respectively, indicating extended rigid chain conformation. The backbone substituted at O-3 and short branching chains probably together induced this conformation.