The suitability of thermogravimetric analysis (TGA) and rheology for predicting analytical
composition of flour was verified. The percentage weight loss of flour samples in
different temperature ranges and their analytical composition determined following
the American Association of Cereal Chemists (AACC) approved methods were correlated.
The moisture content determined by AACC method showed a strong correlation with the
weight loss of dried samples in the temperature range 30 - 125 degrees C. Similarly,
the weight loss of fully swollen samples, determined by TGA in the temperature range
of 30 - 125 degrees C, perfectly correlated with the water-Solvent Retention Capacity
(w-SRC) determined by standard method (AACC). The weight loss in the range 200 - 400
degrees C revealed a good correlation with the starch content, while the weight loss
in the range 400 - 600 degrees C correlated with the gluten content. Finally, the
so-called residue at 600 degrees C (usually attributable to mineral content) correlated
with the ash content (AACC standard method). The rheological parameters (G', G ''
and tan delta) also showed a strong correlation with the analytical composition of
analyzed flours. A perfect correlation was observed between the mineral content and
the elastic modulus, as well as between both G' and G '' and the starch content. As
the resilience of dough samples strongly depends on the relative amount of gliadins
and glutenins, a strong correlation between the Gli/Glu ratio and tan delta was also
found.
