Dietary Fiber and Coronary Heart Disease
Robert E.C. Wildman, Richard S. Bruno in Handbook of Nutraceuticals and Functional Foods, 2019
Cellulose is known to be the most abundant organic molecule on Earth. The molecular structure is similar to amylose in that it is made up of repeating units of the hexose glucose. However, again, the linkages will be 1–4 in nature. Cellulose is produced as a component of the plant cell wall by an enzyme complex called cellulose synthase. Once cellulose chains are formed, they quickly assemble with other cellulose molecules and form microfibrils that strengthen the cell wall. Cellulose, along with certain other fibers (hemicellulose and pectin) and proteins, is found within the matrix between the cell wall layers. This concept is somewhat similar to connective tissue matrix found within bone, tendons, and ligaments in humans. Hemicellulose is different from cellulose in that its monomers are heterogeneous. Hemicellulose will contain varied amounts of pentose and hexose covalently bound in a 1–4 linkage, as well as some branching side chains. Some of the more common and familiar monosaccharides in hemicelluloses are xylose, mannose, and galactose (Figure 10.2). Other monosaccharide subunits include arabinose and 4-O-methyl glucuronic acids.
Contact Urticaria, Dermatitis, and Respiratory Allergy Caused by Enzymes
Ana M. Giménez-Arnau, Howard I. Maibach in Contact Urticaria Syndrome, 2014
Cellulose, the major constituent of plants, is a polysaccharide consisting of linear chains of repeating glucose molecules. The links between the glucose moieties are slightly different than those found in starch, making cellulose much more resistant to hydrolysis. Except for herbivores, most animals cannot efficiently break down cellulose because they lack ruminating chambers colonized by symbiotic bacteria that produce cellulase. Hemicelluloses are different polysaccharides, often coexisting with cellulose, present in the cell wall of most plants. These glucans, mannans, xylans and xyloglucans are hydrolyzed by various hemicellulases such as xylanase, produced by bacteria and fungi that feed on plant matter. Both cellulase and xylanase have found many industrial applications, notably in laundry detergents and in the processing of wood pulp.
Dietary Fibers And Colon Cancer*
Herman Autrup, Gary M. Williams in Experimental Colon Carcinogenesis, 2019
Cellulose — This is a uniform linear polymer with a molecular weight of approximately 600,000 in the pure form and probably more in the natural state. In its primary structure, cellulose consists of about 3000 unbranched β-1,4-D-glucose units in a helix with extensive hydrogen bonding. Because of this β-linkage, cellulose is susceptible to bacterial cellulase but resistant to α-amylase which acts on the α-l,4-D-glucose units in starch. This configuration of cellulose contributes to its strength and insolubility. Other polysaccharides, including hemicellulose and pectin, as well as some nonpoly-saccharides such as lignin and silica, may be absorbed to its surface in food substances. Lignin and silica may also impair the digestibility of cellulose.17
The diet-microbiota axis: a key regulator of intestinal permeability in human health and disease
Published in Tissue Barriers, 2023
Raju Lama Tamang, Anthony F. Juritsch, Rizwan Ahmad, Jeffrey D. Salomon, Punita Dhawan, Amanda E. Ramer-Tait, Amar B. Singh
The claims of beneficial and microbiome-dependent effects of cellulose consumption may be considered controversial, as cellulose is widely considered “inert” as a fermentative substrate and is frequently used as a control in experimental nutrition research where dietary fiber is involved.133 This controversy is compounded by reports from several groups in which mice consuming experimental diets devoid of fermentable fiber develop an abnormal gut physiology characterized by severely atrophied colons and ceca as well as an increased susceptibility to DSS colitis.134–138 Moreover, mice fed high cellulose diets secrete fewer antimicrobial peptides, thereby promoting encroachment of bacteria toward epithelial cells.135 Still others have reported that mice consuming a high cellulose (15% w/w) diet for only one-week experienced increased intestinal permeability compared to mice consuming a high soluble fiber diet (15% psyllium fiber, w/w) and concluded that this effect was microbiome-dependent.139 These discordant results collectively suggest a failure to recognize the totality of the physiological effects of cellulose consumption and that future nutrition studies would benefit from considering the influence of insoluble fiber in their models.
Dietary cellulose induces anti-inflammatory immunity and transcriptional programs via maturation of the intestinal microbiota
Published in Gut Microbes, 2020
Florence Fischer, Rossana Romero, Anne Hellhund, Uwe Linne, Wilhelm Bertrams, Olaf Pinkenburg, Hosam Shams Eldin, Kai Binder, Ralf Jacob, Alesia Walker, Bärbel Stecher, Marijana Basic, Maik Luu, Rouzbeh Mahdavi, Anna Heintz-Buschart, Alexander Visekruna, Ulrich Steinhoff
Dietary cellulose is an insoluble fiber and consists exclusively of unbranched β-1,4-linked glucose monomers. It is the major component of plant cell walls and thus a prominent fiber in grains, vegetables and fruits. Whereas the importance of cellulolytic bacteria for ruminants was described already in the 1960s, it still remains enigmatic whether the fermentation of cellulose has physiological effects in monogastric mammals.6–11 Under experimental conditions, it has been shown that the amount of dietary cellulose influences the richness of the colonic microbiota, the intestinal architecture, metabolic functions and susceptibility to colitis.12,13 Moreover, mice fed a cellulose-enriched diet were protected from experimental autoimmune encephalomyelitis (EAE) through changes in their microbial and metabolic profiles and reduced numbers of pro-inflammatory T cells.14
Understanding the compaction behaviour of low-substituted HPC: macro, micro, and nano-metric evaluations
Published in Pharmaceutical Development and Technology, 2018
Amr ElShaer, Ali Al-khattawi, Afzal R. Mohammed, Monika Warzecha, Dimitrios A. Lamprou, Hany Hassanin
As a bio-based material, cellulose offers unique characteristics such as good biocompatibility, high tensile strength, thermal stability, and superior mechanical properties. Nonetheless, cellulose is poorly soluble in most of the common solvents and lacks the thermoplastic properties desired. Chemical and physical modifications of cellulose structure have been investigated (Hebeish and Guthrie 1981; Roy et al. 2009), primarily via esterification reactions with nitrate and acetic acid derivatives (Klemm et al. 2005) and etherification with methyl, carboxy methyl, and hydroxyalkyl derivatives (Fox et al. 2011).
Related Knowledge Centers
- Bacteria
- Biofilm
- Biopolymer
- Cell Wall
- Glucose
- Glycosidic Bond
- Organic Compound
- Polysaccharide
- Chemical Formula
- Cotton