title: Fructan:fructan 1-fructosyltransferase and inulin hydrolase activities relating to inulin and soluble sugars in Jerusalem artichoke (Helianthus tuberosusLinn.) tubers during storage.
abstract: Influences of harvest time and storage conditions on activities of fructan:fructan1-fructosyltransferase (1-FFT) and inulin hydrolase (InH) in relation to inulin and soluble sugars of Jerusalem artichoke (Helianthus tuberosusL.) tubers were investigated. Maturity affected 1-FFT-activity, inulin contents, and inulin profiles of the tubers harvested between 30 and 70 days after flowering (DAF). Decreases in 1-FFT activity, high molecular weight inulin, and inulin content were observed in late-harvested tubers. The tubers harvested at 50 DAF had the highest inulin content (734.9 ± 20.5 g kg-1DW) with a high degree of polymerization (28% of DP >30). During storage of the tubers, increases in InH activity (reached its peak at 15 days of storage) and gradual decreases in 1-FFT activity took placed. These changes were associated with inulin depolymerization, causing decreases in inulin content and increases in soluble sugars. As well, decreasing storage temperatures would retain high inulin content and keep low soluble sugars; and freezing at -18 °C would best retard 1-FFT, InH, and inulin changes.
authors.affiliation: School of Food Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, 30000 Thailand.
authors.forename: Sukanya
authors.initials: S
authors.lastname: Maicaurkaew
authors.affiliation: Department of Plant Science and Agricultural Resources, Peanut and Jerusalem Artichoke for Functional Food Research Group, Khon Kaen University, Khon Kaen, 40000 Thailand.
authors.forename: Sanun
authors.initials: S
authors.lastname: Jogloy
authors.affiliation: Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN 47907 USA.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Hamaker
authors.affiliation: School of Food Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, 30000 Thailand.
authors.forename: Suwayd
authors.identifier: 0000-0003-4323-0124
authors.initials: S
authors.lastname: Ningsanond
keywords: 1-FFT activity; Fructan; InH activity; Inulin content; Soluble sugars