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Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. [1] Lignins are particularly important in the ...
Flax seeds and sesame seeds contain high levels of lignans. [1] [8] The principal lignan precursor found in flaxseeds is secoisolariciresinol diglucoside.[1] [8] Other foods containing lignans include cereals (rye, wheat, oat and barley), soybeans, tofu, cruciferous vegetables, such as broccoli and cabbage, and some fruits, particularly apricots and strawberries. [1]
Kraft lignin from black liquor, which is produced in much higher amounts, may be processed into sulfonated lignin. The lignin is first precipitated by acidifying the liquor with CO 2 then washed (other methods for isolation exist). Reaction with sodium sulfite or sodium bisulfite and an aldehyde under a basic environment completes sulfonation.
Lignin is a biopolymer which combines with cellulose to form the lignocellulose complex, an important complex that confers strength and durability to plant cell walls. Lignin is a macromolecule formed from the combination of many phenolic aromatic groups via oxidative coupling. Because of its high stability, lignin is incapable of being broken ...
lignin is a heterogeneous, highly crosslinked polymer akin to phenol-formaldehyde resins. It is derived from 3-4 monomers, the ratio of which varies from species to species. The crosslinking is extensive. Being rich in aromatics, lignin is hydrophobic and relatively rigid. Lignin confers structural integrity to plants.
Polyphenols, such as lignin, are larger molecules (macromolecules). Their upper molecular weight limit is about 800 daltons, which allows for the possibility to rapidly diffuse across cell membranes so that they can reach intracellular sites of action or remain as pigments once the cell senesces.
The inclusion of lignin makes the secondary cell wall less flexible and less permeable to water than the primary cell wall. [4] In addition to making the walls more resistant to degradation, the hydrophobic nature of lignin within these tissues is essential for containing water within the vascular tissues that carry it throughout the plant.
Lignin is a polymer with an inert nature that forms the structures of woody plants. The ratio of the three monolignols as well as their linkages varies depending on the plant species. For example, Norway spruce lignin is almost entirely derived from coniferyl alcohol, whereas paracoumaryl alcohol is the main monomer of lignin in grasses. [4]
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