PHYSICO-CHEMICAL CHARACTERISTICS OF DIETARY FIBRE FRACTIONS IN THE GRAINS OF TETRAPLOID AND HEXAPLOID TRITICALES: A COMPARISON WITH WHEAT AND RYE

摘要

The contents of water-soluble (SDF) and insoluble dietary fibre (IDF) and DF-associated protein, sugar composition of noncellulosic polysaccharides (NCP) as well as viscosity of cereal slurries were investigated in tetraploid (4x) and hexaploid (6x) triticales compared to wheat and rye. The SDF content found in 4x triticale (3.3% of dry matter) was significantly higher (P<0.05) than those in 6x triticale and wheat (1.7 and 1.9%, respectively), but lower than that in rye (4.8%). Consequently, the level of soluble arabinoxylans was significantly higher (P<0.05) in 4x triticale (1.53%) than in 6x triticale (0.91 %). However, it was intermediate when compared to wheat and rye (0.85% and 2.78%, respectively). In rye 33% of arabinoxylans was soluble in water, 22% in 4x triticale while only 15% in 6x triticale and wheat. The differences in sugar content and composition between 6x and 4x triticales were evident mainly in the SDF fraction, which may be attributed to higher proportion of rye to wheat genomesin 4x triticale (2:2) than in 6x triticale (2:4). Nevertheless, the water-soluble arabinoxylans from grains of 4x and 6x triticales were characterized by extremely high degrees of substitution, as evidenced by their arabinose-to-xylose ratio (Ara/Xyl),exceeding those of parent wheat and rye. The viscosity of 4x triticale slurry had a significant, positive correlation with total content of arabinoxylans (r=0.82, P<0.05). The DF-associated protein represented 16-24% of total amount of protein in the grain.