Table 2.
Natural polymers used in this study and their food and pharmaceutical applications.
Gum | Structure | Common uses and applications |
---|---|---|
| ||
Gum Arabic | Main chain consisting of β-(1,3) linked galactose units with branches of β-(1,6) linked galactose and arabinose with terminal rhamnose and glucuronic acid. Contains 2% of protein within the structure[1]. | Suspending agent, emulsifying agent, binder in tablets, demulcent and emollient in cosmetics[2,3], osmotic drug delivery[4]. |
Pectin | Linear chain of α-(1,4) linked galacturonic acid units, with up to 80% of these occurring as methyl esters. Contains up to 4% of rhamnose units, which are then linked to arabinose, galactose and xylose side chains[1]. | Thickening agent, suspending agent, stabilizer[2,5], floating beads[6], controlled drug delivery (ocular[7], transdermal[8], colonic[9,10]). |
Alginate | Linear structure consisting of (1,4) linked β-mannuronic and α-guluronic acids, with proportions depending on the source[1]. | Thickening agent, stabilizer[2,5], sustained release agent[11,12], film coatings[13], mucoadhesive systems[14]. |
| ||
Chitosan | Deacetylated derivative of chitin composed of randomly distributed β-(1–4)-linked glucosamine (deacetylated unit) and N-acetyl-glucosamine (acetylated unit)[15]. | Tissue engineering[16–22], wound dressing[23,24] , antibacterial[25], drug delivery[26]. |
| ||
κ-carrageenan | Disaccharide repeat unit of β-(1,3) linked galactose-4-sulfate and α-(1,4) linked 3,6-anhydrogalactose residues[1]. | Thickening agent, gelling agent, stabilizer[2], laxative[5], tablet matrix[27], controlled release agent[28–30]. |
| ||
Guar gum | Main chain consisting of β-(1,4) mannose units with galactose with α-(1,6) linked branches. Mannose to galactose ratio is 2:1[1]. | Binder, disintegrant, thickening agent, emulsifier, laxative[2,5], sustained release agent[31], colon targeted drug delivery[32]. |
Tara gum | Main chain consisting of β-(1,4) mannose units with galactose with α-(1,6) linked branches. Mannose to galactose ratio is 3:1[1]. | Thickener, stabilizer[2,5], controlled release agent[33–35]. |
Locust bean gum | Main chain consisting of β-(1,4) mannose units with galactose with α-(1,6) linked branches. Mannose to galactose ratio is 4–4.5:1[1]. | Thickener, stabilizer[2,5] and controlled release agent (oral, buccal, colonic, ocular and topical)[36]. |
Konjac | Main chain consisting of β-(1,4) mannose and glucose units with α-(1,3) linked branches. Mannose to glucose ratio is 1.6:1[1]. | Gelling agent, thickener, emulsifier, stabilizer[2], Controlled release formulation[37–40]. |
[1]: Williams and Phillips, 2003a; [2]: Williams and Phillips, 2003b; [3]: Beneke et al., 2009; [4]: Lu, 2003; [5]:Prajapati, 2013; [6]: Sriamornsak et al., 2007; [7]:Giunchedi, 1999; [8]: Musabayane et al., 2003; [9]:Vandamme, 2002; [10]: Wong et al., 2011; [11]: Hodsdon, 1995; [12]: Maiti, 2009; [13]: Rajsharad et al., 2005; [14]: Kesavan et al., 2010; [15]: Islam et al., 2017; [16]: Chung, 2002; [17]: Chung, 2002; [18]: Shalumon, 2009; [19]: Kawakami, 1992; [20]: Hu, 2004; [21]: Wang, 2005; [22]:Mattioli-Belmonte, 1999; [23]: Kumar, 2010; [24]: Madhumathi, 2010; [25]: Rahman Bhuiyan, 2017; [26]:Ali and Ahmed, 2018; [27]:Picker, 1999; [28]: Leong, 2011; [29]: Li, 2014; [30]: Mahdavinia et al., 2015; [31]: Al-Saidan, 2005; [32]: Chourasia and Jain, 2004; [33]: Ma et al., 2017; [34]: Rutz, 2013; [35]:Zeng et al., 2005; [36]: Dionísio and Grenha, 2012; [37]: Alvarez-Mancenido, 2008; [38]: Fan, 2008; [39]: Du, 2006; [40]:Wang, 2014.