Solid-state C-13 NMR of cell walls in wheat bran

Cell walls from wheat bran were examined intact by cross-polarization, magic-angle spinning C-13 NMR to determine their polymer composition. The carbohydrate part of the C-13 spectrum was typical of graminaceous cell walls having cellulose and arabinoxylans as their main components. Only a little lignin was observed in the spectrum, but signals from the hydrocarbon chains of cutin were particularly obvious. It is suggested that cutin, rather than lignin, plays an important role in protecting wheat bran from microbial degradation in the rumen and in the human gut and that the hydrophobic properties of the cutin are likely to be responsible for some of its nutritional properties.