Determination of the content of buckwheat and wheat flours in bread using GC-MS and multivariate analysis

This paper reports on the analysis of carbohydrate components in bread crusts, made of seven controlled mixtures of buckwheat and wheat flour. These were mono-, disaccharides and some heterocyclic compounds derivatized into their corresponding trimethylsilyl ethers and analysed by a gas chromatography-mass spectrometry system. Selected ion monitoring (SIM) chromatograms with m/z signals of 73, 204 and 217 were selected from total ion current (TIC) chromatograms, as the selected ions are known to be characteristic for silylated carbohydrates. Programmes AMDIS (Version 2.66) and NIST (MS Search Version 2.0), and NIST08 library (National Institute of Standards and Technology, Gaithersburg, Maryland, USA) were used to confirm the presence of carbohydrates. The aim was to evaluate applicability of multivariate analysis of the stated components to determination of the content of buckwheat flour in bread, made of a mixture of buckwheat and wheat flours. It was sufficient to use the principal component analysis and a dendrogram to clearly present the proportion of buckwheat flour in bread.