A simple and accurate method for determining wheat grain fructan content and average degree of polymerization.
An improved method for the measurement of fructans in wheat grains is presented. A mild acid treatment is used for fructan hydrolysis, followed by analysis of the released glucose and fructose with high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Not only the amount of fructose set free from fructans but also the released glucose can be quantified accurately, allowing determination of the average degree of polymerization of fructans (DP(av)). Application of the mild acid treatment to different grain samples demonstrated that a correction should be made for the presence of sucrose and raffinose, but not for stachyose or higher raffinose oligosaccharides. The fructan content and DP(av) of spelt flour, wheat flour, and whole wheat flour were 0.6%, 1.2%, and 1.8% of the total weight and 4, 5, and 6, respectively. Validation experiments demonstrate that the proposed quantification method is accurate and repeatable and that also the DP(av) determination is precise.
Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), KULeuven, Leuven, Belgium. Joran.Verspreet@biw.kuleuven.be
Joran
J
Verspreet
Annick
A
Pollet
Sven
S
Cuyvers
Rudy
R
Vergauwen
Wim
W
Van den Ende
Jan A
JA
Delcour
Christophe M
CM
Courtin
D005630:Fructans / Q000032:analysis* / Q000737:chemistry*; D005632:Fructose / Q000032:analysis; D005947:Glucose / Q000032:analysis; D006868:Hydrolysis; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results; D012639:Seeds / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry*
D005630:Fructans; D011108:Polymers; D005632:Fructose; D005947:Glucose