Sixteen wheat cultivars originating from different countries and genot
ypes and characterised by different technological properties were anal
ysed for the amount and proportion of omega- and alpha-type and gamma-
type gliadin subgroups. The optimal extraction of gliadin from flour w
as achieved with 60% (v/v) aqueous ethanol after pre-extraction with a
salt solution. The separation and quantitative determination was perf
ormed by reversed-phase high-performance liquid chromatography on C-18
silica gel. The amount of both total gliadin and subgroups revealed d
istinct inter-cultivar differences. Within the subgroups, the alpha-ty
pe gliadins were generally present in greatest amount, followed by the
gamma-type gliadins, whereas the omega-gliadins were present at lower
levels. A strong statistical relationship was found between the prote
in content of the flours and the amounts of total gliadin, alpha-type
and gamma-type gliadins. Other flour properties (baking volume, SDS-se
dimentation volume, dough resistance and extensibility) were correlate
d only weakly with gliadin contents, with only omega 1,2-gliadins and
gamma(A)- gliadins showing moderate negative and positive effects, res
pectively. The proportions of omega- and alpha-type and gamma-type gli
adins found within the total gliadin fraction covered broad ranges (al
pha: 43.9-59.9%, gamma: 30.5-45.6%, omega: 6.2-20.0%). The proportions
of the gliadin subgroups were to some extent related to the genotype
of the cultivar. Thus, high proportions of omega-gliadins (17-20%) wer
e typical for wheat/rye hybrids. In view of the inter-cultivar variati
on observed, the value of immunochemical assays developed for the anal
ysis of total gliadin in food is restricted if the reactivity of the a
ntibodies used is not directed to all types of gliadin components but
to the minor subgroups of omega-gliadins.