Promoting structure formation by high pressure in gluten-free flours

In order to evaluate the potential of high pressure (HP) treatment to improve the functional properties of gluten-free flours, the effect of HP on the rheological properties of three gluten-free batters was investigated. Buckwheat, white rice and teff batters (40 g/100 g) were treated for 10 min at 200, 400 or 600 MPa. Changes in the microstructure of the batters after HP-treatment were observed using scanning electron microscopy. Pasting profiles revealed HP-induced starch gelatinisation. Furthermore, Lab-on-a-Chip capillary gel electrophoresis revealed protein polymerisation by thiol/disulphide-interchange reactions in white rice and teff batters. For buckwheat proteins however, no such cross-linking mechanism was observed, which was explained by the absence of free sulfhydryl groups. An increase in viscoelastic properties at higher pressures was observed, and could be explained by the modifications occurring in starch and protein structure. Overall, this study has shown that HP-treatment has the potential to improve functional properties of gluten-free batters.