University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Markus Regner
(2021):
EFFECTS OF SOURDOUGH FERMENTATION AND SCALDED FLOUR ON WHEAT-SORGHUM BREAD QUALITY.
Master / Diploma Thesis - Institut für Lebensmitteltechnologie,
BOKU-Universität für Bodenkultur,
pp 112.
UB BOKU
obvsg
- Abstract:
- In this thesis the potential of sorghum flour for baking purposes was evaluated, with focus on improvement of quality parameters by application of sourdough fermentation and the use of scalded flour. Besides physical parameters such as specific volume, porosity and crumb firmness also protein digestibility was a core research field. Sourdough fermentation was examined as tool for a potential increase of protein digestibility. Sourdough fermentation of three different sorghum flours was successfully carried out by backslopping with spontaneous starter cultures. Breads were produced with a flour composition of 60% wheat flour and 40% sorghum flour (variety Armorik) and an increased dough yield level, because levels typical for wheat bread (158 - 180) resulted in inferior physical bread quality. The application of scalded sorghum flour did not further improve bread properties, contrary to literature reports about scalded wheat flour. Neither an improvement of shelf life by higher crumb moisture nor a reduction of crumb firmness could be achieved. The concentration of total phenolic compounds of sorghum flours was not changed by sourdough fermentation. Pepsin protein digestibility of sorghum flour, which was evaluated by pepsin digestion could not be improved by sourdough fermentation, contrary, a loss of digestibility from 60,14% to 51,47% occurred during fermentation (variety Armorik). Artificial acidification with organic acids and following incubation for 24h led to different and mostly higher protein digestibility than sourdough fermentation. However, artificially acidified doughs did not show a higher protein digestibility than the native sorghum flours. Baked breads even showed a lower protein digestibility when sourdough fermentation had been applied for an extended time such as 4 or 24 h of proofing. Overall, it can be concluded that typical bread-quality improving technologies which are well-established for wheat-baking do not necessarily work for sorghum.
- Beurteilende(r): Schönlechner Regine
- 1.Mitwirkender: Rumler Rubina