Pectin in foods

Authors: Cameron, Randall - Randy

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/20/2018
Publication Date: 11/22/2018
Citation: Cameron, R.G. 2018. Pectin in foods. In: Encyclopedia of Food Chemistry. Elsevier. pp. 208-213. https://doi.org/10.1016/B978-0-08-100596-5.21590-4.
DOI: https://doi.org/10.1016/B978-0-08-100596-5.21590-4

Interpretive Summary: Pectin, a complex polysaccharide, is a major component of non-lignified cell walls of plants. Its food-related technological functions are numerous and mirror many of its biological functions. As a naturally occurring component of raw or processed foods and as an additive in formulated foods it influences texture and rheological properties. Pectin’s chemistry and functionality are dominated by galacturonic acid, which is organized largely as a linear polymer. A variable proportion of the galacturonic acid residues may have a charge. Thus, extensive variability can be found in both the total amount of charge as well as how the charge is distributed within the polymer. In situ pectin appears to exist as an interconnected network associated with cellulose and hemicellulose. Once extracted from plant tissue pectin is believed to exist as a population of molecules in which no two are identical. Structural details, how they relate to functionality and how they can be engineered to impart predictable functional properties will be addressed in this review.

Technical Abstract: Pectin, a complex polysaccharide, is a major component of non-lignified cell walls of dicotyledonous and some monocotyledonous plants. Its food-related technological functions are numerous and mirror many of its biological functions. As a naturally occurring component of raw or processed foods and as an additive in formulated foods it influences texture and rheological properties. Structurally pectin is a block hetero co-polymer. Pectin’s chemistry and functionality are dominated by galacturonic acid, which is organized largely as a linear homogalacturonan polymer. A variable proportion of the galacturonic acid residues may have a charge masking methyl ester on the C6 carboxylic acid. Thus, extensive variability can be found in both the total amount of charge as well as how the charge is distributed within the homogalacturonan region. The other major co-polymeric constituent has a repeating disaccharide of rhamnose and galacturonic acid and is believed to be dispersed between, and flanked by the homopolymeric galacturonic acid regions. Relatively short chain galactans, arabinans and arabinogalactans may be attached to the rhamnose residues. In situ pectin appears to exist as an interconnected network associated with cellulose and hemicellulose. Once extracted from plant tissue pectin is believed to exist as a population of molecules in which no two are identical. Structural details, how they relate to functionality and how they can be engineered to impart predictable functional properties will be addressed in this review.