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Polysaccharides: An Overview
Published in Shakeel Ahmed, Aisverya Soundararajan, Pullulan, 2020
S. Vijayanand, Ashwini Ravi, Aisverya Soundararajan, Annu, P. N. Sudha, J. Hemapriya
Pectin is a complex polysaccharide found in the middle lamella of cell wall. The concentration of pectin gradually decreases from primary wall to plasma membrane [81]. Pectins are produced in the initial stages of primary cell wall growth and form one third of the dry cell wall [72, 123]. Pectin is present in all dicot plants and also in monocots except grass membrane [81]. In the 1930s, the commercial production of pectin was started by Hermann Herbstreith who explained the use of pectin [20]. The structural prediction of pectin was difficult since it varies with source, during isolation, processing plant material, and storage [124, 171]. But pectins were thought to be made up of D-galacturonic acid joined together by α (1→4) linkage [10] (Fig. 1.4). Structure of pectin [58].
Tensile Properties of Sugar Palm Fiber-Reinforced Polymer Composites
Published in R. Jumaidin, S.M. Sapuan, H. Ismail, Biofiller-Reinforced Biodegradable Polymer Composites, 2020
R.A. Ilyas, S.M. Sapuan, M.S.N. Atikah, R. Ibrahim, R. Syafiq, M.D. Hazrol, A. Nazrin, M.I.J. Ibrahim
Field emission scanning electron microscope (FESEM) pictures of SPFs were taken to investigate the structure of SPFs to reveal their homogeneity and micrometric dimensions, and are also shown in Figure 14.1. Microscopic examination of the cross section of SPFs was depicted in Figure 14.1c and d. As shown in Figure 14.1c and d, the view from the outer to the inner part showed that SPFs consist of a middle lamella, a primary cell wall, a secondary cell wall, and a tertiary cell wall, buildup around an opening, the lumen [19,21]. The middle lamella as seen in Figure 14.1d, which surrounds the cell wall is mainly composed of pectins (macromolecules of galacturonic acid) that hold fibers together into a bundle, with a size of around 1.98 ± 0.15 μm. The interior of the SPFs consists of primary cell wall, secondary cell wall, and lumen. The primary cell wall is made of cellulose (a polymer based on glucose units) fibrils in an organic matrix of amorphous hemicelluloses and lignin, proteins, and low methyl-esterified pectins, with an average diameter of around 10.38 ± 0.57 μm. The secondary cell wall consists of three layers of cellulose fibrils with different axial orientations that are bound by lignin. Primary cell wall and secondary cell wall also provide mechanical support to the plant. Figure 14.1d shows a lumen with a thickness of around 3.72 ± 0.15 μm.
Drying of Agricultural Crops
Published in Guangnan Chen, Advances in Agricultural Machinery and Technologies, 2018
D. M. C. C. Gunathilake, D. P. Senanayaka, G. Adiletta, Wiji Senadeera
Blanched fruits and vegetables have higher color attributes than non-blanched ones because of thermal inactivation of undesirable enzymes (peroxidase and lipoxygenase), and a resultant decrease in the rate of enzymatic deterioration of fruits and vegetables. Furthermore, blanching can also limit the degradation of both chlorophylls and carotenoids. However, the blanching treatment causes undesirable changes in the properties of the food, such as the loss of soluble nutrients (sugars, minerals, and vitamins). Moreover, it causes loss of aroma and negatively impacts the sensory properties associated with texture. In particular, the levels of texture softening during the blanching process can be observed by scanning electron microscopy, which has been found to result in physical changes in cell structure (such as cell separation and cell damage) of blanched carrot tissues. It was found that they appeared greater than those in untreated raw tissue. This breakdown in cellular structure has been also observed in mushrooms. Moreover, pectin is degraded and solubilized from the cell wall and the middle lamella between adjacent cell walls. This has led to a loss of adhesion between cells and turgor pressure, which ultimately destroys the membrane integrity.
Potential of Catharanthus roseus applied to remediation of disparate industrial soils owing to accumulation and translocation of metals into plant parts
Published in International Journal of Phytoremediation, 2023
V. Soumya, Basira H, P. Kiranmayi
Pectin is a structurally complex polysaccharide that constitutes the major component of primary cell walls in plants and is vital for cellular adhesion and cell wall plasticity (Mohnen 2008). Due to its acidic nature, it can effectively bind heavy metals for their easier uptake. The middle lamella which is a pectinaceous interface depends on the formation of intermolecular links between pectin molecules and is important for the adhesion of neighboring cells (Jarvis et al. 2003). Among the diverse functional properties of Pectin, the one clearly known and common to various sources since the earliest studies (Ricardo et al. 2019) is the formation of gel under specified conditions. The characterization and the gelling properties of pectin depend upon the source, methods of extraction and the purification steps involved prior to analysis (Pinheiro et al. 2008). It has been recently shown that the type of acid strongly influences the macromolecular state and gelling properties of pectin (Yapo 2009). Citric acid is the least pectin degrading, depolymerizing and de-esterifying extracting agent which leads to pectin isolates with the best gelling properties. Extraction of pectin in this study was therefore carried out using citric acid.
Surface treated Pteris vittata L. pinnae powder used as an efficient biosorbent of Pb(II), Cd(II), and Cr(VI) from aqueous solution
Published in International Journal of Phytoremediation, 2018
Smruthi G. Prabhu, Govindan Srinikethan, Smitha Hegde
The changes observed are attributed to the targeted action of the chemicals onto the specific components of the plant cell. From the literature, it is learnt that sodium hydroxide (NaOH) promotes the removal of lignin and a part of hemicelluloses, but not the cellulose (Karp et al. 2015; Jӧnsson and Martín 2016). Hemicellulose of the plant cell links the pectin of middle lamella and cellulose of primary cell wall, holding them intact. Upon disintegration of hemicelluloses, these links are broken causing the cell wall component, cellulose to loosen. In the study, low concentration of NaOH was employed to cause favorable changes to PPV. As at higher concentrations, complete disintegration of hemicelluloses causes undesired separation of cellulosic fibers from the biosorbent surface that could negatively affect the biosorption capacity (Karp et al. 2015). Low concentrations of NaOH resulted in the surface erosion of NPV, but not the separation of cellulosic fibers from the biosorbent surface.