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onsdag 15 augusti 2018

MAISSIN (Zea Mays) ligniinikomponentista tuoretta tietoa 2018 . Maissikuitu.

Maissin kuitupitoisuus  Fineli.fi
Maissijyvät, 5% kuitua.
Polenta, karkea maissijauho, kuitu 4%
Gluteeniton Corn Flakes, kuitu 1 %
Maissi, tacokuori, kuitu 1%
Pakastevihannes Amerikansekoitus, porkkana-papu-parsakaali-paprika-maissi, kuitu 9%.
jne
https://fineli.fi/fineli/fi/index, hakusana Maissi


 Maissin LIGNIINISTÄ  ja  fenolisista polymeereistä


https://www.ncbi.nlm.nih.gov/pubmed/29665690
Abstract
The structure of the phenolic polymer in maize grain fibers, with 5.5% Klason lignin content, has been studied.
 For this, the milled wood lignin (MWL) and dioxane lignin (DL) preparations were isolated and analyzed. The data indicated that the lignin in maize fibers was syringyl rich, mostly involved in β-aryl ether, resinol, and phenylcoumaran substructures.
2D NMR and derivatization followed by reductive cleavage (DFRC) also revealed the occurrence of associated ferulates together with trace amounts of p-coumarates acylating the γ-OH of lignin side chains, predominantly on S-lignin units.
 More interesting was the occurrence of diferuloylputrescine, a ferulic acid amide, which was identified by 2D NMR and comparison with a synthesized standard, that was apparently incorporated into this lignin.
 A phenylcoumaran structure involving a diferuloylputrescine coupled through 8-5' linkages to another diferuloylputrescine (or to a ferulate or a guaiacyl lignin unit) was found, providing compelling evidence for its participation in radical coupling reactions.
 The occurrence of diferuloylputrescine in cell walls of maize kernels and other cereal grains appears to have been missed in previous works, perhaps due to the alkaline hydrolysis commonly used for composition studies. KEYWORDS:
2D NMR; Maize kernels; ferulates; hydroxycinnamoyl amides; lignin monomers
10.1021/acs.jafc.8b00880


018 Apr 25;246:360-378. doi: 10.1016/j.foodchem.2017.11.012. Epub 2017 Nov 3.

Relevance, structure and analysis of ferulic acid in maize cell walls.

Bento-Silva A1, Vaz Patto MC1, do Rosário Bronze M2.
Phenolic compounds in foods have been widely studied due to their health benefits. In cereals, phenolic compounds are extensively linked to cell wall polysaccharides, mainly arabinoxylans, which cross-link with each other and with other cell wall components. In maize, ferulic acid is the phenolic acid present in the highest concentration, forming ferulic acid dehydrodimers, trimers and tetramers. The cross-linking of polysaccharides is important for the cell wall structure and growth, and may protect against pathogen invasion. In addition to the importance for maize physiology, ferulic acid has been recognized as an important chemical structure with a wide range of health benefits when consumed in a diet rich in fibre. This review paper presents the different ways ferulic acid can be present in maize, the importance of ferulic acid derivatives and the methodologies that can be used for their analysis.

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