QUANTITATIVE NMR ASSESSMENT OF POLYSACCHARIDES IN COMPLEX FOOD MATRICES

摘要

In many food products polysaccharides are a critical ingredient for providing stable rheological properties. Food polysaccharides show a wide structural diversity and already provide benefits when formulated at low levels. Taken together with strong matrix interactions these factors complicate the quantitative assessment of polysaccharide in complex product formulations. Most analytical approaches described so far rely on qualitative identification of polysaccharides and quantification based on monosaccharide analysis. NMR has typically been applied for qualitative purposes but recently also progress has been made in semi-quantification. Whereas NMR presents an ideal tool for quantification of low-molecular weight species, its deployment for absolute quantitative assessment of polysaccharides is less straightforward. This is primarily due to broadened and overlapping lineshapes, which compromises NMR signal integration. By hydrolysis of polysaccharides spectral resolution is improved, which allows for straightforward, rapid and absolute quantification, without the use of analytical standards. This procedure however discards the secondary and tertiary structure of polysaccharides, hence compromising their identification.