2024-03-28T20:41:31Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1132292020-11-13T13:29:42Zcom_10261_15com_10261_6col_10261_268
00925njm 22002777a 4500
dc
Rencoret, Jorge
author
Prinsen, Pepijn
author
Gutiérrez Suárez, Ana
author
Martínez, Ángel T.
author
Río Andrade, José Carlos del
author
2015
The structure of the lignin from brewer’s spent grain (BSG) has been studied in detail. Three different lignin preparations, the so-called “milled-wood” lignin (MWL), dioxane lignin (DL), and cellulolytic lignin (CEL), were isolated from BSG and then thoroughly characterized by pyrolysis GC/MS, 2D-NMR, and derivatization followed by reductive cleavage (DFRC). The data indicated that BSG lignin presents a predominance of guaiacyl units (syringyl/guaiacyl ratio of 0.4−0.5) with significant amounts of associated p-coumarates and ferulates. The flavone tricin was also present in the lignin from BSG, as also occurred in other grasses. 2D-NMR (HSQC) revealed that the main substructures present are β-O-4′ alkyl-aryl ethers (77−79%) followed by β-5′ phenylcoumarans (11−13%) and lower amounts of β-β′ resinols (5−6%) and 5-5′ dibenzodioxocins (3−5%). The results from 2D-NMR (HMBC) and DFRC indicated that p-coumarates are acylating the γ-carbon of lignin side chains and are mostly involved in condensed structures. DFRC analyses also indicated a minor degree of γ-acylation with acetate groups, which takes place preferentially on S lignin (6% of S units are acetylated) over G lignin (only 1% of G units are acetylated).
Journal of Agricultural and Food Chemistry 63: 603−613 (2015)
http://hdl.handle.net/10261/113229
10.1021/jf505808c
Brewers’ spent grains
lignin
Py-GC/MS
TMAH
HSQC
DFRC
Isolation and structural characterization of the milled wood lignin, dioxane lignin, and cellulolytic lignin preparations from brewer´s spent grain