Pearling reduces the contents of insoluble fibre, protein, ash
and free lipids, but increases the contents of starch and b-glucan by
the removal of outer layers, including the hull (palea and lemma),
bran (pericarp, testa) and germ (embryo), which are richer in
insoluble fibre, protein, ash and lipids and poorer in starch and
b-glucan than the endosperm (Quinde et al., 2004; Quinde-Axtell
et al., 2006). The composition and physical characteristics of barley
grain have large influences on the processing properties and product
quality of foods prepared from or incorporated with pearled barley
and/or barley flour. Hulless barley requires little or no effort to
remove the hull during threshing or processing and would be more
suitable for processing and human consumption than hulled barley.
On the other hand, hulled barley is preferred to hulless barley for
malting and brewing because of the contribution of the hull to beer
flavour and as a filtering aid during brewing.Waxy starch genotypes
not only deliver unique physical properties to food products but also
contain higher contents of protein and b-glucan than genotypes
with regular starch composition. However, because human consumption
of barley and barley-containing food products has been
insignificant as compared to other cereal grains, the development of
new processes and food products has been neglected and there has
been little effort to define quality requirements for food uses. The
significance of b-glucan and tocols for human nutrition is well
known, but little is known about the functional properties of
b-glucan for making food products. Some of the traits preferred for
specific food applications are known through investigations on
incorporating barley into wheat-based food products.