Extraction and in vitro fermentation of rye bran fractions

Rye bran was fractionated on a pilot scale into water-extractable, alkali-e xtractable and unextractable fractions. The fractions were enzymatically di gested to partially remove starch and protein. The enzyme treated Substrate s were fermented in vitro using a human faecal inoculum. The water- and alk ali-extractable fractions were fermented faster than the unextractable frac tion and rye bran itself. However, the extent of fermentation after 24 h wa s similar in each case. The production of gases and short-chain fatty acids correlated well with the consumption of neutral sugars. All the rye substr ates enhanced the molar proportion of propionic and butyric acids, among th e short chain Fatty acids. (C) 2001 Academic Press.