Abstract:
The replacement of gluten in dough products poses a major challenge. Preparing zein doughs
in dilute acetic acid and lactic acid, such as produced during sourdough fermentation, was
investigated. Increasing acid concentrations (0.7, 1.3 and 5.4% [v/v]) increased zein
extensibility and reduced the stress and related parameters. Preparation of zein-maize starch/-
rice doughs in dilute organic acids improved dough properties to the extent that the doughs
could hold air and be inflated into a bubble by Alveography. Further, they exhibited similar
Stability (P), Distensibility and deformation energy (W) to wheat flour dough. Confocal laser
scanning microscopy revealed an ordered linear fibril network in zein and zein-rice flour
doughs prepared in the dilute acids, which became uniform with increasing acid
concentration. SDS-PAGE showed that the acids did not hydrolyse or polymerise the zein.
FTIR indicated that the acidic conditions slightly increased the proportion of α-helical
conformation in the zein doughs, possibly as a result of deamination. This conformational
change may be responsible for the considerably improved zein dough properties. Zein doughs
prepared in dilute organic acids show potential as a gluten replacement in gluten-free
formulations.