Fructan

A fructan is a polymer of fructose molecules. They occur in foods such as:
 * Artichokes
 * Asparagus
 * Green beans
 * Leeks
 * Onions (including spring onion)
 * Wheat

In animal fodder, fructans also appear in grass, with dietary implications for horses and other equidae.

There are 3 types of fructans:
 * 1) Inulin - linear fructans generally linked by β(2→1) glycosidic bonds
 * 2) Levan - linear fructans generally linked by β(2→6) glycosidic bonds
 * 3) Graminan - branched fructans linked by both β(2→1) and β(2→6) glycosidic bonds

Fructan content of various foods
Artichoke, Jerusalem: 16.0-20.0%

Artichoke, Globe: 2.0-6.8%

Asparagus: 1.4-4.1%

Barley kernels (very young): 22%

Cheese spread: 4.5%

Chocolate: 9.4%

Onion: 1.1-10.1%

Rye bran: 7%

Rye grain: 4.6-6.6%

Wheat flour: 1-4%

Pasta: 1-4%

White bread: 0.7-2.8%

Functions
Plants storing their food as fructans are able to thrive at low temperatures since fructans confer tolerance to freezing. They bind to membranes, thereby helping to keep cells intact.

General references

 * Sugar - Chemical, Biological and Nutritional Aspects of Sucrose. John Yudkin, Jack Edelman and Leslie Hough (1971, 1973). The Butterworth Group. ISBN 0-408-70172-2