Effect of Yeast Glutathione on Rheological Properties of Wheat Dough
HAIOU WANG1, G. KARADJOV2, Z. ROSHKOVA2 and A. ANGELOV2
1Wuxi University of Light Industry, R.P. China
2Higher Institute of Food and Flavour Industries, Deptartment of Biotechnology, BG-4002 Plovdiv, Bulgaria
HAIOU WANG, G. KARADJOV, Z. ROSHKOVA and A. ANGELOV, 2000. Effect of yeast glutathione on rheological properties of wheat dough. Bulg. J. Agric. Sci, 6: 327-331
The effects of yeast derived glutathione (GSH) on wheat dough were tested through farinografic experiments. Tests were carried out with three yeast brands: commercial compressed, active dry baker's yeast and a selected glutathione biosynthesis deficient mutant Saccharomyces cerevisiae. Changes occurring in intra– and extracellular glutathione during fermentation of the three yeast brands on a defined medium were monitored. Comparing the results, we found that the total GSH concentration decreases in the following order: compressed yeast, active dry yeast, mutant yeast, which corresponds to the exrtacellular GSH concentrations as well. However, the ratio of GSH content in cells and broth was kept relatively constant within the range 1.03 to 1.86. Farinograms obtained show that the rheological properties (consistency and mixing tolerance) of dough worsen with the fermentation and mixing time proceeding. Results from the dough fermentation with the mutant yeast strain were compared to those from dough prepared with the commercial strains. The rheological properties of fermented dough were closely related, indicating that the level of glutathione contributed by yeast was to a large extent not available to react with flour proteins.
Key words: rheology, wheat dough, yeast, glutathione