Pectin purification from plant materials

Pectin, an intricate anionic polysaccharide, is found in the middle lamella of higher plants’ cell walls. It is employed as a gelling agent, thickener, stabilizer, and dietary fiber due to its unique properties. To obtain this carbohydrate polysaccharide, it must be extracted from its sources, namely different parts of fruits and vegetables, in various ways. After the extraction process, owing to the presence of other cell wall constituents such as cellulose microfibrils, hemicellulosic materials, starches, and lignin in the crude aqueous extract, varying methods are used to purify pectin. These methods are predominantly based on the disruption of pectins and solvent molecules interactions (e.g., alcohol precipitation or drying) as well as the complex formation of anionic pectins and cationic materials (e.g., pectin–protein and pectin–metal complexes). Each purification method leads to obtaining pectins with distinctive chemical configurations and characteristics due to the difference in their separation mechanisms. These differences can be in terms of the amounts of sugar contents, galacturonic acid, degree of methylation, the size of isolated pectic fractions, and so forth. Each method has some advantages and disadvantages, and the selection of each method should be based on the costs, needs, and characteristics of the desired pectin. Graphical Abstract