title: Potato tuber pectin structure is influenced by pectin methyl esterase activity and impacts on cooked potato texture.
abstract: Although cooked potato tuber texture is an important trait that influences consumer preference, a detailed understanding of tuber textural properties at the molecular level is lacking. Previous work has identified tuber pectin methyl esterase activity (PME) as a potential factor impacting on textural properties. In this study, tuber PME isoform and gene expression profiles have been determined in potato germplasm with differing textural properties as assessed using an amended wedge fracture method and a sloughing assay, revealing major differences between the potato types. Differences in pectin structure between potato types with different textural properties were revealed using monoclonal antibodies specific for different pectic epitopes. Chemical analysis of tuber pectin clearly demonstrated that, in tubers containing a higher level of total PME activity, there was a reduced degree of methylation of cell wall pectin and consistently higher peak force and work done values during the fracture of cooked tuber samples, demonstrating the link between PME activity, the degree of methylation of cell wall pectin, and cooked tuber textural properties.
authors.affiliation: Plant Products and Food Quality Programme, Scottish Crop Research Institute, Dundee DD2 5DA, UK.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Ross
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Wright
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: McDougall
authors.forename: Alison G
authors.initials: AG
authors.lastname: Roberts
authors.forename: Sean N
authors.initials: SN
authors.lastname: Chapman
authors.forename: Wayne L
authors.initials: WL
authors.lastname: Morris
authors.forename: Robert D
authors.initials: RD
authors.lastname: Hancock
authors.forename: Derek
authors.initials: D
authors.lastname: Stewart
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Tucker
authors.forename: Euan K
authors.initials: EK
authors.lastname: James
authors.forename: Mark A
authors.initials: MA
authors.lastname: Taylor
mesh_terms: D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism*; D005511:Food Handling; D010368:Pectins / Q000737:chemistry* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D035281:Plant Tubers / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D011198:Solanum tuberosum / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D010368:Pectins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase