Determination of cell wall ferulic and p-coumaric acids in sugarcane bagasse

• Published in: Analytica chimica acta 2005-11, Vol.552 (1), p.207-217
• Main Authors: Xu, Feng, Sun, Run-Cang, Sun, Jin-Xia, Liu, Chuan-Fu, He, Bei-Hai, Fan, Jin-Shan
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Exact sciences and technology; Ferulic acid; NMR; p-Coumaric acid; Phenolic compounds; Spectrometric and optical methods; Sugarcane bagasse
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2005.07.037

To completely determine ferulic and p-coumaric acids and related phenolic compounds in the cell walls of sugarcane bagasse (SCB), a second mild alkaline hydrolysis of the alkali-soluble lignin preparations and acid hydrolysis of the 90% acidic dioxane-soluble lignin fractions were performed, which released 48.8% of the total ester-linked p-CA and 43.8% of the total esterified FA from the alkali-soluble lignin fractions, and 38.8% of the total ether-linked p-CA and 38.5% of the total ether-linked FA from the 90% acidic dioxane-soluble lignin preparations, respectively. Based on the dry weight, it has been found that the SCB contained 1.76% p-CA and 1.29% FA as well as minor quantities of related phenols. Further study of the solubilized lignin samples by combining with UV and FT-IR spectroscopy, and 1H and 13C NMR spectroscopy confirmed that a predominant amount of p-CA (69.5–76.4%) is ester-linked to the cell wall components, mainly to lignin. On the other hand, about half of the FA (44.0–55.0%) is esterified to the cell wall hemicelluloses, and the remaining half of the FA is also be etherified through the phenolic oxygen to lignin component in the cell walls of SCB.