Pectin structure and biosynthesis

The structure, function, and biosynthesis of plant cell wall pectic polysaccharides.

With the arising of global climate change and resource shortage, in recent years, increased attention has been paid to environmentally friendly materials. Trees are sustainable and renewable materials, which give us shelter and oxygen and remove carbon dioxide from the atmosphere. Trees are a primary resource that human society depends upon every day, for example, homes, heating, furniture, and aircraft. Wood from trees gives us paper, cardboard, and medical supplies, thus impacting our homes, school, work, and play. All of the above-mentioned applications have been well developed over the past thousands of years. However, trees and wood have much more to offer us as advanced materials, impacting emerging high-tech fields, such as bioengineering, flexible electronics, and clean energy. Wood naturally has a hierarchical structure, composed of well-oriented microfibers and tracheids for water, ion, and oxygen transportation during metabolism. At higher magnification, the walls of fiber cells have an interes...

https://www.fpl.fs.fed.us/documnts/pdf2016/fpl_2016_zhu001.pdf

Wood-Derived Materials for Green Electronics, Biological Devices, and Energy Applications.

Pectin or pectic substances are collective names for a group of closely associated polysaccharides present in plant cell walls where they contribute to complex physiological processes like cell growth and cell differentiation and so determine the integrity and rigidity of plant tissue. They also play an important role in the defence mechanisms against plant pathogens and wounding. As constituents of plant cell walls and due to their anionic nature, pectic polysaccharides are considered to be involved in the regulation of ion transport, the porosity of the walls and in this way in the control of the permeability of the walls for enzymes. They also determine the water holding capacity. The amount and composition of pectic molecules in fruits and vegetables and other plant produce strongly determine quality parameters of fresh and processed food products. Pectin is also extracted from suitable agro-by-products like citrus peel and apple pomace and used in the food industry as natural ingredients for their gelling, thickening, and stabilizing properties. Some pectins gain more and more interest for their health modulating activities. Endogenous as well as exogenous enzymes play an important role in determining the pectic structures present in plant tissue, food products, or ingredients at a given time. In this paper functional and structural characteristics of pectin are described with special emphasis on the structural elements making up the pectin molecule, their interconnections and present models which envisage the accommodation of all structural elements in a macromolecule. Attention is also given to analytical methods to study the pectin structure including the use of enzymes as analytical tools.

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Pectin, a versatile polysaccharide present in plant cell walls

Structure–function relationships of immunostimulatory polysaccharides: A review

Pectic substances: From simple pectic polysaccharides to complex pectins—A new hypothetical model

Pectins from citrus peel cell walls contain homogalacturonans homogenous with respect to molar mass, rhamnogalacturonan I and rhamnogalacturonan II

Cote d'Ivoire (Ivory Coast) is the world's largest cocoa producer with about 1.2-1.6 million tons per year. This co-generates approximately ten times of fresh cacao pod husks, which are hitherto left unutilized to decompose in plantations. This study aims at evaluating the cacao pod husks potential for antioxidant-dietary fiber compounds. Cacao pod husk product was used for the extraction of dietary fiber and phenolic compounds. The results showed that the cacao pod husk product contained ∼ 60.0% of total dietary fiber, of which non-starchy polysaccharides accounted for > 70.0%, and a total phenolic content of ∼69.0 mg Gallic acid equivalent/g, thereby indicating that it was an antioxidant dietary fiber-rich product. It also exhibited interesting antioxidant properties, as judged by 2,2-Diphenyl-1-picrylhydrazyl (85.0% inhibition percentage and EC50 = 25.0 g/g), 2,2'-Azinobis-(3- ethylbenzthiazoline-6-sulphonic acid) diammonium salt (52.0 µmol Trolox equivalent/g), and Ferric reducing antioxidant power (130.0 µmol Trolox equivalent/g) assays. The total antioxidant capacity of the cacao pod husk product was significantly higher (P < 0.05) than the total antioxidant capacity of fermented-and-roasted cocoa hull and kernel products. The total antioxidant capacity seemed to result from synergistic interactions among various compounds endowed with antioxidant capacity, including soluble phenolics, condensed tannins, and possibly pectic substances. Cacao pod husks therefore appeared to be a valuable source of antioxidant dietary fiber-rich food materials which may be used to significantly reduce the risk of development of miscellaneous free radical-induced diseases.

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Adding Value to Cacao Pod Husks as a Potential Antioxidant-Dietary Fiber Source

Since their first discovery in 1790–1825, pectins are still fascinating plant and food scientists who continue to carry out numerous structural as well as functional studies on them. This great interest of scientists for pectins is accounted for by their large spectrum of (bio)functionalities, starting from their natural location in plant cell walls as bioactive components for cell growth, defense, and protection via diverse manufactured food and nonfood products as techno-functional (gelling, emulsifying, film-forming, etc.) agents to terminate in human welfare as health-benefit (prebiotic, anticomplementary, antioxidant, anticancer, etc.) agents. The extraordinary functional versatility of pectins is thought to be intimately related to fine structure. Unfortunately, structurally, pectins are extremely diversified that establishment of structure-function relationship appeared so far a difficult task to go through. On the other hand, the extended structural variability of pectins presages for the finding of new functions hitherto unknown. Nevertheless, for some structurally well-known pectic cobiopolymers such as homogalacturonan, solid evidence for structure-related functions, especially gelling properties, has been provided, including new insights very recently. After a brief introduction on the “pectin structural repertoire,” the main sources of industrial pectins will be exposed, followed by a succinct structural description of the different pectic block cobiopolymers, commonly referred to as “pectic polysaccharides.” Finally, some remarkable structure-related functions, namely, gelling, emulsifying/emulsion-stabilizing, and antitumor properties of pectins will be revisited in the light of the latest work.

Beda Marcel Yapo

Papers

Pectic substances: From simple pectic polysaccharides to complex pectins—A new hypothetical model

Pectins from citrus peel cell walls contain homogalacturonans homogenous with respect to molar mass, rhamnogalacturonan I and rhamnogalacturonan II

Adding Value to Cacao Pod Husks as a Potential Antioxidant-Dietary Fiber Source

PecticPolysaccharides and Their Functional Properties

Utilisation of model pectins reveals the effect of demethylated block size frequency on calcium gel formation.