Author:

Keywords:

nonstarch polysaccharides, starch polysaccharides, soluble arabinoxylans, cereal pentosans, endosperm, protein, fractions, features, quality, linkage, Science & Technology, Physical Sciences, Life Sciences & Biomedicine, Chemistry, Applied, Food Science & Technology, Chemistry, NONSTARCH POLYSACCHARIDES, STARCH POLYSACCHARIDES, SOLUBLE ARABINOXYLANS, CEREAL PENTOSANS, ENDOSPERM, PROTEIN, FRACTIONS, FEATURES, QUALITY, LINKAGE, 0301 Analytical Chemistry, 0703 Crop and Pasture Production, 0908 Food Sciences, Food Science, 3006 Food sciences, 3401 Analytical chemistry

Abstract:

Water-extractable arabinogalactan-peptides (WE-AGP) were isolated from flour of eight different wheat cultivars (harvest year 1996). Little structural variation in WE-AGP of flour of the different wheat cultivars was observed. The arabinose-to-galactose (A/G) ratio of WE-AGP varied between 0.66 and 0.73. Methylation analysis showed that the proportion of beta-1,3-galactopyranosyl residues is almost equal for the different WE-AGP samples (10.2-11.1%). More variation was observed for the proportion of the beta-1,6-galactopyranosyl residues (9.4-13.0%) and beta-1,3,6-galactopyranosyl residues (76.0-80.1%). The H-1-nuclear magnetic resonance spectra (D2O, 85 degrees C, 300 MHz) were comparable, and gel permeation analysis consistently yielded a narrow peak with an apparent molecular weight between 5.0 x 10(4) and 10.0 x 10(4). Interpretation of the results was facilitated by alpha-L-arabinofuranosidase debranching of WE-AGP. For flour samples of 18 wheat cultivars (10 from 1994 harvest, eight from 1996 harvest), the variation in percentage of water-extractable arabinoxylan (WE-AX) (0.31-0.78% of dry matter) was much larger than the variation in percentage of water-extractable arabinogalactan (WE-AG) (0.24-0.33%). The ratio of WE-AX to WE-AG for flour samples of different wheat cultivars varied between 1.00 and 2.44.