Milling of whole grain rye to obtain fractions with different dietary fibre characteristics

Rye was separated by dry-milling into three fractions enriched in different rye grain tissue (pericarp/testa, aleurone and endosperm). The fractions v aried considerably in gross chemical composition: the starch content ranged from 3.0 g/100 g dm in the pericarp/testa to 78.2 g/100 g dm in the endosp erm, and the content of dietary fibre (DF) from 6.5 g/100 g dm in the endos perm to 73.3 g/100 g dm in the pericarp/testa. Protein, fat, ash and phosph orous were concentrated in the aleurone fraction. DF characteristics also d iffered largely between the rye milling fractions. Arabinoxylans (AX) compr ised the majority of DF components in all samples. but on DF basis the mill ing fractions had different concentrations of lignin, cellulose and beta-gl ucans. Moreover, a wide range in arabinose to xylose ratio of the water-une xtractable AX (0.35-1.02) and in the proportion of water-extractable AX (14 -70% of total AX) implied that variation in AX structure was obtained. Rye breads intended for a nutritional study were made from the milling fraction s. Tt is concluded that the breads can be used to study the influence of DF characteristics on the colonic fermentation processes in monogastrics. (C) 1999 Academic Press.