Chemistry Reference
In-Depth Information
2.1 INTroDuCTIoN
2.1.1 What Is scFos?
Fructans have been defined as “any compound where one or more fructosyl-
fructose linkages constitutes a majority of linkages … fructan is used to name mole-
cules that have a majority of fructose residues, whatever the number is” (Roberfroid,
2005a). Fructans therefore represent a heterogeneous group, and as such, many dif-
ferent possible chemical entities exist. Fructans can vary with respect to the follow-
ing (Roberfroid, 2005a):
•
Source—Plant, bacteria, and fungi
•
Chain composition—All fructose or mostly fructose
•
Linkages—2,1 and 2,6
•
Degree of polymerization (DP)—Plant fructans do not exceed DP of 200; however,
bacterial fructans can have a DP as high as 100,000
Architecture—Linear, branched, or cyclic
•
•
Functionality—Physiology and food science
Because of the heterogeneity of the fructan family, subclass classifications have
evolved with their own set of chemical and physiological properties. Figure 2.1 rep-
resents different classes of linear fructans, categorized according to chain length.
The subclass called inulin represents a higher-molecular-weight group, with DP <
200. In contrast, the subclass called oligofructose has a lower molecular weight, with
DP < 10 (Roberfroid, 2005a). The oligofructose subgroup can be further subdivided
into the group called short-chain fructo-oligosaccharides (scFOS).
Commercially, scFOS consists of low-molecular-weight linear chains syn-
thesized by enzymatic fermentation from sucrose; however, the short chains also
exist in nature. scFOS is clearly a unique subset of the broader oligofructose group
because the fermentation process results in linear chains of three to five sugar units
only, with every chain terminated by glucose. In the broader oligofructose group, DP
can extend to 10, and chains can be terminated by either glucose or fructose, which
Linear Fructans
Inulin: DP < 200
Oligofructose: DP < 10
scFOS:
GF
2
- GF
4
Figure 2.1
Classes of linear plant fructans, categorized by chain length.
