posters 5th Asia-Pacific NMR Symposium 2013

Spectroscopic Characterisation of Polysaccharides in Foods Before and After Digestion (#123)

Bernadine M Flanagan 1 , Barbara A Williams 1 , Michael J Gidley 1
  1. ARC Centre of Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, St Luica, Queensland, Australia

Starch and non-starch polysaccharides (NSPs) in whole grains and processed foods are an important part of human and animal diets. Food texture, palatability and digestibility are all influenced by the physical and chemical nature of these polysaccharides. To fully understand polysaccharide structure and function, it is desirable to study whole foods as eaten rather than extracting individual components. It is also important to be able to examine polysaccharides within the complex digesta matrix to determine how they are digested and fermented. Using a range of nuclear magnetic resonance (NMR) spectroscopy techniques it was possible to analyse polysaccharides in whole foods and in whole digesta without the need for laborious isolation methods. 13C CP/MAS (cross polarization/magic angle spinning) was used to ascertain the ratios of starch and cellulose and the percentage crystallinity of starch and cellulose in foods and feeds before and after small intestinal digestion. Samples were also studied using 13C DP/MAS (direct polarization/magic angle spinning) to detect the presence of NSPs such as arabinoxylan following small intestinal digestion and large intestinal fermentation. The samples were further analysed using solution state 1H NMR to quantify the amount of arabinoxylan in digesta samples.