Sustainable Polysaccharides from Malvaceae Family: Structure and Functionality

Abstract

Abstract The structure, technological and biological functionality of polysaccharides extracted from members of Malvaceae family plants have been evaluated. In addition to glycosidic linkages that are regularly observed in pectic polysaccharides, several members of this family, including lacebark, grewia, durian, and some fractions of kola have high levels of 3,4-linked galacturonic acid residues. This specific linkage is commonly found in RG-II structures casting doubts over the true macromolecular characteristics of rhamnogalacturonan segments in these plants, commonly presumed as RG-I. Several members of the family exhibit unique linkages and functionalisation not encountered in other species, such as 4-linked α-galactose that is unique to lacebark leave polysaccharides or terminal α-galactose in the kola tree bark and okra pectin. Polysaccharides from lacebark and grewia are only acetyl esterified as opposed to those from okra that are both acetyl and methyl esterified whereas those from baobab, durian and cacao have very low amounts of acetyl groups. Polysaccharides from Malvaceae family present opportunities for further technological development in the area of biomaterial science as they have a broad range of functionality allowing them to be used as emulsifiers, film-forming agents, controlled delivery vehicles, or rheology modifiers. Research on the biological activity of polysaccharides from Malvaceae is still nascent but early findings are reassuring, as a broad range of functionalities (e.g., anti-inflammatory, antioxidant or modulation of metabolism) have been reported.