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GENETICALLY DETOXIFIED GRAINS
molecular weight proteins. High-molecular weight proteins (x - and y-type subunits)
comprise the HMW subunits of glutenins; glutamine, glycine, and proline represent
70% of total residues. Medium-molecular weight group consists of w-gliadins; 80% of
the amino acids is due to glutamine, proline, and phenylalanine, but cysteine and
methionine, i.e. sulphur containing amino acids, are almost absent. Low-molecular
weight proteins consist of a-, b-, g-gliadins and LMW subunits of glutenins; they are
rich in sulphur containing amino acids.
Functional properties of gluten proteins
Although the only known function of these proteins is to act as storage proteins, by
releasing nitrogen for the germinating seed, their biochemistry structure has a crucial
2,6
role in providing the unique baking quality of wheat . Both LMW and HMW have not
only intrachain but also interchain disulphide bonds allowing them to crosslink other
glutenin and gliadin peptides, which results in the formation of beta-spirals. During the
baking process, CO
2
is produced by yeast fermentation and is trapped in the beta-spiral
three dimensional net. Glutenins spirals become extended but maintain the capacity to
return to the colloid state. So, elasticity and cohesivity of the dough system are due to
the cross-linked nature of the glutenin subunits, mainly the high molecular weight
glutenins. On the other hand, soluble monomeric gliadins guarantee extensibility and
viscosity to the dough (Fig. 1).
Coeliac toxicity of gliadins and glutenins
Since the demolition of these proteins to single amino acids results on loss of coeliac
C
C
N
N
N
TECHNOLOGICAL
PROPERTIES
N N C C C
HMWx HMWy LMW g a
Elasticity & Cohesivity
Extensibility & Viscosity
Fig. 1. Schematic representation of gluten protein components. Black segments unique
sequence; white segments repeating sequence; ] intrachain disulphide bond; - interchain
disulphide bond; C C-terminal sequence; N N-terminal sequence; HMWx high-molecular
weight glutenins x-type subunit; HMWy high-molecular weight glutenins y-type subunit;
LMW low-molecular weight glutenins; g-gliadins; a-gliadins.