Determination of Fructans in Plants: Current Analytical Means for Extraction, Detection, and Quantification

Fructans are one of the most significant groups of sucrose‐derived water‐soluble carbohydrates in higher plants and microbes. They are largely differentiated by the linkage type between the terminal sucrose and the adjacent fructosyl units as well as by the degree of polymerisation ranging from oligomers (DP 3-9) to polymers (DP >10 up to a few hundred) and whether they are linear or highly branched structures (Section 2). The rapidly increasing scientific evidence for fructans functioning as reserve and structural carbohydrates as well as having antioxidant and immunomodulatory/signalling potential has motivated a recent boost in both fundamental research and in potential applications for food and nutrition. In contrast, analytical methods for fructan determination and discrimination have developed slowly. In this article, we summarise the current knowledge concerning methodologies for fructan analysis. We focus on fructan extraction and isolation (Section 3), quantification (Section 4), separation and detection (Section 5), structural characterisation (Section 6) as well as approaches for tissue‐specific and spatially resolved analysis (Section 7), and nondestructive detection of fructans (Section 8) in various plant materials. Finally, we discuss future perspectives for fructan analysis in plant tissues, also in the context of investigating structure-function relationships (Section 9).