SOP for the determination of galacturonic content. Biophysical characterization of quality traits, WP2

Mestres Christian, Ollier Léa, Domingo Romain, Otegbayo Bolanle Omolara, Rolland-Sabaté Agnès, Dutheil de la Rochère Aliénor. 2022. SOP for the determination of galacturonic content. Biophysical characterization of quality traits, WP2. Montpellier : RTBfoods Project-CIRAD, 12 p.

https://doi.org/10.18167/agritrop/00605

Document technique et de recherche

Prévisualisation

Version publiée - Anglais
Sous licence

.
RTBfoods_SOP_Determination of Galacturonic Content.pdf
Télécharger (495kB) | Prévisualisation

Résumé : Cell walls in plants are mainly composed of polysaccharides. Among them, pectin, cellulose and hemicellulose are composed of various sugars residues (acidic: galacturonic acid in pectins; or neutral: rhamnose, galactose, arabinose, xylose, glucose in cellulose, hemicellulose and pectic side chain). This fine composition affects the structure but also the behavior and mechanical properties of cell walls and consequently the textural properties of RTB foods. In raw products and/or after cooking some cell wall components are soluble (eg. some pectin). This procedure seeks to determine the galacturonic acid level extracted from pre-dried (dried or freeze-dried) RTBs. This method gives the galacturonic acid content of cell walls extracted with different solvents, independently of the neutral sugars content. Pectin are first extracted at intermediate temperature (55°C) to facilitate their extraction while limiting their chemical and enzymatic degradation and the extraction of starch (temperature below starch gelatinization). Extracted pectin are then hydrolyzed by hot sulphuric acid in order to obtain sugar residues and their furfural derivatives. Neutral sugars gave brown derivatives whereas free galacturonic acid is quantified by colorimetry after reaction with MHDP which produces a specific fuschia pink complex with a maximum absorption at 520 nm (Blumenkrantz and Asboe-Hansen, 1973). Galacturonic acid content is calculated after subtracting the brown colour (at 520 nm) generated by neutral sugar hydrolysis.

Mots-clés libres : Pectin, Galacturonic acid, Extraction, Colorimetric measurement

Agences de financement hors UE : Bill and Melinda Gates Foundation, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Centro Internacional de Agricultura Tropical, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, James Hutton Institute

Projets sur financement : (FRA) Breeding RTB Products for End User Preferences

Auteurs et affiliations