Polysaccharides from defatted sesame seed kernel: Structural characterization and potential applications

• Polysaccharides of sesame kernel meal (SMP) were firstly characterized • SMP exhibited excellent free radical scavenging activity • SMP-2 was composed of a linear backbone of (1→5)-linked α-L-arabinofuranosyl units The defatted sesame kernel is a high-quality source of polysaccharides. However, there is a lack of research on the extraction, purification, structural characterization, and application of polysaccharides from defatted sesame kernel. This study primarily aimed to characterized the structural features of polysaccharides from sesame kernel and investigated their potential applications. Polysaccharides were extracted from defatted sesame kernel using ultrasound-assisted alkali extraction with 5% (w/w) KOH at 50°C for 30 min. Following decolorization, deproteinization, and column chromatography with NaCl elution (0, 0.1, 0.3, 0.5, and 0.7 mol/L), five purified polysaccharide fractions (SMP-1, SMP-2, SMP-3, SMP-4, SMP-5) were obtained. The composition and antioxidant activity of polysaccharides were analyzed. SMP-2 was the dominant fraction (36.5%) and composed of arabinose (42.9%), galactose (33.3%), rhamnose (10.2%), glucuronic acid (6.8%), and others. The linkage types of SMP-2 are mainly characterized by a linear backbone of (1→5)-linked α-L-arabinofuranosyl units. Additionally, the study found that SMP-1, SMP-2, and SMP-3 remained stable below 250°C, suggesting their potential use in thermally processed foods requiring heat-resistant polysaccharides. SMP-4 and SMP-5 exhibited pronounced free radical scavenging activities. These findings provide valuable insights for the in-depth research and industrial application of sesame polysaccharides.