Quantitative analysis of wheat starch–water suspensions by pulsed NMR spectroscopy measurements

Abstract

A rapid and non-destructive method, based on pulsed NMR spectroscopy, has been developed for the study of wheat starch–water interaction. It involves a Gaussian fitting of the FID signals from liquid and solid phases obtained by pulsed NMR spectroscopy, resulting in an exact and repeatable quantification of these different phases. Moreover, the standard addition method in the range of a water/starch ratio greater than 0.55 allows the use of water as an internal reference. This reference signal is in good agreement with the total amount of hydrogen atoms in the sample, regardless of the solid/liquid ratio. This allows, from wheat starch suspensions in deuterium oxide, a determination of the starch proportion which has a ‘liquid’ behaviour (7.5%) and of the quantity of exchangeable hydroxyl groups (2.6:3) in the wheat starch granule.