Free sugars and non-starch polysaccharide contents of good and poor malting varieties of wheat and their malts

The yield and composition of low molecular weight sugars and non-starch polysaccharides (NSP) of a good- and a poor-malting variety of wheat and their malts were determined. There were seven, four and six-fold increases in total sugars, sucrose and maltose, respectively, on 120 h germination in both varieties, the increase being higher in the good-malting variety than in the poor-malting variety. The poor-malting variety contained slightly (11.7%) higher levels of total NSP than the good-malting variety (10.9%). The uronic acid formed 2.5 to 23.3% of the different NSP fractions, the highest being in EDTA-extractable (EDTAE) fractions. The hexose content of the cold water-soluble fraction decreased from 63.4 to 20% on malting in the good-malting variety but its content remained the same in the poor-malting variety. Mannose was detected only in the EDTAE fraction of the good-malting variety and its concentration decreased from 24.2 to 4.6% on malting. Malt samples from both varieties contained slightly higher levels of hemicellulose A, hemicellulose B and cellulosic fractions, and lower levels of EDTAE NSP fractions. The water-soluble fraction was 45% of the total NSP of the good-malting variety and 28% of the poor-malting variety.