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Applications of Green Polymeric Nanocomposites
Published in Satya Eswari Jujjavarapu, Krishna Mohan Poluri, Green Polymeric Nanocomposites, 2020
Mukesh Kumar Meher, Krishna Mohan Poluri
Gellan gum is a long-chain extracellular polysaccharide, secreted by Sphingomonas elodea bacteria. Gellan biopolymer is an anionic linear heteropolysaccharide possessing repeating units of tetrasaccharide molecules such as α-l-rhamnose, β-d-glucose and β-d-glucuronic acid in the ratio of 1:2:1 with l-glycerate (Okiror and Jones 2012). In industry, gellan gum is manufactured by a fermentation process in an appropriate medium. Generally, gellan gum is synthesized in two acyl forms – high-acyl (HA) and low-acyl (LA) gellan gum. The gelation properties vary according to their acyl substitution form, as LA requires gel-promoting cations whereas HA produces gels by cooling down the hot gellan solutions (Sworn 2009a). Due to its gelling properties, gellan gums are widely used in the food and pharmaceutical industries (Krasaekoopt and Bhandari 2012, Morales and Ruiz 2016, Philp 2015).
Pharmaceutical Applications of Gellan Gum
Published in Amit Kumar Nayak, Md Saquib Hasnain, Dilipkumar Pal, Natural Polymers for Pharmaceutical Applications, 2019
Shakti Nagpal, Sunil Kumar Dubey, Vamshi Krishna Rapalli, Gautam Singhvi
Among various polysaccharide based natural polymer, gellan gum has been investigated for various pharmaceutical and biomedical application. Gellan gum is a bacterial polysaccharide which is obtained from Sphingomonas elodea. It was identified to possess a commercial advantage in 1978 during an extensive soil-water borne bacterial screening program by C.P. Kelco (USA). Produced from the strains of Sphigomonas, Gellan gum consists of rod-shaped, gram-negative, strict aerobe, chemoheterotrophic bacteria which produce yellowish pigmented colonies and consists of glycosphingolipids in their cell wall. Gellan is a linear polymer, anionic in nature and has a repeating sequence of tetra-saccharides consisting of two residues of β-D-Glucose (L-Rhamnose and β-D-Glucuronate) (Figure 4.1). The polysaccharide, which is biosynthesized has L-glyceryl substituents on O (2) and an acetyl group at O (6) of glucose unit in tetra-saccharide repeat sequences. During its commercial production, both the substituents get removed when treated with hot alkali and fermentation broth (Prajapati et al., 2013).
Application of Nanotechnology in the Safe Delivery of Bioactive Compounds
Published in V Ravishankar Rai, Jamuna A. Bai, Nanotechnology Applications in the Food Industry, 2018
Behrouz Ghorani, Sara Naji-Tabasi, Aram Bostan, Bahareh Emadzadeh
Gellan is an anionic extracellular polysaccharide produced by the microorganism Sphingomonas elodea. It is available in two forms, namely, low acyl (deacetylated) and high acyl gellan with different gelation methods. Low acyl gellan forms a thermoreversible gel upon cooling in the presence of gelling cations, while the high acyl gellan form gels without the need for cations. The resulting gels have variable textures depending on the degree of acetylation and concentration of the divalent cations present (Phillips and Williams 2009). Gellan gum is widely used in the food industry as a gelling, stabilizing, and suspending, film-forming, and encapsulation agent. These applications are possible due to its reactivity with the cations and its ability to form a gel at remarkably small concentrations in comparison with other hydrocolloids, such as carrageenan, alginate, pectin, or gelatin (Ogawa, Matsuzawa, and Iwahashi 2002). In addition, biocompatibility, lack of toxicity, biodegradability, the stability in an acidic environment and against enzymes in the GI tract, temperature resistance, the ionotropic gelation ability with formation of mechanically stable gels, the ability to form films that act as barriers to oil absorption make it an attractive ingredient in the food industry (Iurciuc et al. 2105; Ferris, Gilmore, and Wallace 2013; Yang et al. 2013). Gellan gum can be applied to encapsulate various bioactive compounds to obtain functional foods (Iurciuc et al. 2105; Tan, Heng, and Chan 2011). Gellan gum is a suitable biopolymer for the delivery of probiotics due to its functional properties: resistance to many enzymes in the GI tract and high resistance to pH and temperature and gellan combined with xanthan was used to cover Bifidobacterium species (Sun and Griffiths 2000) (Table 12.1).
Novel freeze-drying matrix for enhancing viability of probiotic supplemented milkshake during simulated in vitro digestion
Published in Preparative Biochemistry & Biotechnology, 2022
Chakravarthy Muninathan, Megavarshini Poompozhilan, Srisowmeya Guruchandran, Adithya Jairam Viswanath Kalyan, Nandhini Devi Ganesan
The combination of Whey protein (WP) with different polysaccharides is studied for enhancements in the protective effect of the encapsulation matrix.[4] However, the protective effects of naturally occurring microbial polysaccharides are less exploited. Pullulan, xanthan and gellan are natural water-soluble exo-polysaccharides synthesized by Aureobasidium pullulans, Xanthomonas campestris and Sphingomonas elodea respectively.[5] These microbial polysaccharides exhibit dietary fiber properties and nourish gut microbiota. The prebiotic property of soluble polysaccharides and the possibilities of using them as a delivery vehicle for probiotics has increased the interest in using them as protective agents.[6] Other goals of using soluble viscous dietary fibers as thickeners in food are due to their ability in modulating digestion and post-prandial glycaemic response[7] which presents an important opportunity to understand their supportive role in retaining cell viability under stressed conditions.
Plant gums for sustainable and eco-friendly synthesis of nanoparticles: recent advances
Published in Inorganic and Nano-Metal Chemistry, 2020
This class of plant polysaccharides such as arabinoxylans (found in primary and secondary cell walls of plants), gellan and xanthan gum, composed of three different monomers.[92] Cereal xylans such as wheat arabinoxylans are extremely used in food industries for producing huge number of various types of foods. The most prominent group of non-starch polysaccharides in the endosperm walls of wheat is water extractable and non-water extractable arabinoxylans.[93] They are composed of a main backbone of β − 1,4 linked D-xylopyranosyl residues.[94] Cereal xylans are mainly substituted with (1→2)- and/or (1→3)-linked α-L-arabinofuranosyl residues, but they can also carry (1→2)-linked α-D-glucopyranosyluronic acid or its 4-O-methyl ether and acetyl substituents.[95] Gellan gum, an extracellular polysaccharide elaborated by the micro-organism Sphingomonas elodea (ATCC 31461) previously referred to as Pseudomonas elodea.[96] This gum is a linear anionic polysaccharide composed of tetrasaccharide (1,3-β-D-glucose, 1,4-β-D-glucuronic acid, 1,4-β-D-glucose and 1,4-α-L-rhamnose) repeating-units,[97] approximately 25% contain an O-acetyl group linked to C-6 of one of the β-d-glucopyranosyl residues.[98]