Characterization and antioxidant activity of differentiated fractionation lignin from corn stover.

Lignin contains many chemical functional groups with multiple biological activities. However, the heterogeneity of lignin such as complex structure and high polydispersity, and poor dissolution performance hinders its value-added application. In this study, it was found that there was a significant difference in the solubility of the chemical components of corn stover alkali-extracted lignin-carbohydrate complex (CSALCC) in a 0.6 M NaHCO solution. Herein, CSALCC was fractionated using a 0.6 M NaHCO solution, hot water, acid precipitation, and macroporous adsorption resin D101 column chromatography to afford fraction F1-1, F2, and F3-1. To demonstrate the improvement in composition, water solubility and antioxidant activity of the fractions. The characterization techniques UV, FTIR, NMR, TGA, SDS-PAGE and GPC were employed. Antioxidant activities were evaluated by ABTS, ORAC and ferric reducing power assay. F1-1 consists mainly of hemicellulose and is soluble in deionized water. F2 is a more water-soluble lignin than CSALCC, which is conducive to the development of value-added products of lignin in aqueous systems. F3-1 was acidic-soluble lignin with the highest total polyphenol content of all fractions, and exhibited higher water solubility, antioxidant properties and UV absorption. F3-1 may have potential application in cosmetics, pharmaceuticals, the food processing field.