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United States Department of Agriculture

Agricultural Research Service

Title: Characterization of Fructan Oligomers from Species of the Genus Allium L.

Authors
item Ernst, M - UNIVERSITY OF HOHENHEIM
item Chatterton, N
item Harrison, Philip
item Matitschka, G - UNIVERSITY OF HOHENHEIM

Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 25, 1997
Publication Date: N/A

Interpretive Summary: Storage tissue of leaf bases from species of onion were analyzed to determine their water soluble carbohydrate composition. The onions studied can be divided into three groups according to their fructan profiles: (1) species with relatively high amounts of larger fructan polymers, (2) species with relatively high amounts of small fructan polymers up to a degree of polymerization of about 15, and (3) species with both fructo-oligosaccharides and larger fructan polymers. As a typical pattern for those species with lower degrees of polymerization four major fructan series with exclusively (2,1) fructosyl-fructose linkages have been characterized: (1) a neokestose-series with chain elongation on both sides of the glucose, (2) a neokestose-series with chain elongation only at the side of glucose, (3) An inulin-series, and (4) an inulo-n-ose series without a terminal glucose. While the first three fructan series were present in rather high concentrations in all samples with high amounts of small fructans, the inulo-n-ose series was detectable in most samples, but in varying concentrations.

Technical Abstract: Storage tissue of leaf bases from species of the genus Allium [A. cepa L. var. cepa (onion, 6 cvs.), A. cepa L. var. ascalonicum (shallot, 7 cvs.), A. ampeloprasum L. var. porrum (leek, 3 cvs.), A. schoenoprasum L. (chives), A. sativum L. (garlic), A. fistulosum L. (Japanese bunching onion / Welsh onion), A. tuberosum Rottl. ex. spr. (Chinese chives / Nira), and other species] were analyzed to determine their water soluble carbohydrate composition. The investigated Allium species can be divided into three groups according to their fructan profiles: (1) species with relatively high amounts of larger fructan polymers, (2) species with relatively high amounts of small fructan polymers up to a degree of polymerization of about 15, and (3) species with both fructo- oligosaccharides and larger fructan polymers. As a typical pattern for those species with lower degrees of polymerization four major fructan series with exclusively (2,1) fructosyl-fructose linkages have been characterized: (1) a neokestose-series with chain elongation on both sides of the glucose, (2) a neokestose-series with chain elongation only at the side of glucose, (3) An inulin-series, and (4) an inulo-n-ose series without a terminal glucose. While the first three fructan series were present in rather high concentrations in all samples with high amounts of small fructans, the inulo-n-ose series was detectable in most samples, but in varying concentrations.

Last Modified: 7/22/2014
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