Epsilon Archive for Student Projects

Abstract

The breadmaking quality of wheat is generally attributed to its gluten proteins, which form the viscoelastic, gas-retaining network of wheat flour dough. The composition of gluten proteins, in particular protein molecular size distribution, is known to influence the rheological properties and baking quality of wheat flour. Vital gluten (VG) is a gluten protein concentrate that is added to wheat flour to improve dough and bread characteristics. However, VG is currently sold with limited quality specifications, including information regarding its protein composition. The aim of this project was to (1) investigate how the gluten protein molecular size distribution, loaf volume and dough rheological properties are affected in VG wheat flour blends by the addition of different VGs to wheat flour, and (2) compare chromatographic and rheological methods for describing VG quality in an industrial setting. Twelve wheat flour blends with 4% (w/w) of commercial VG were produced and evaluated in terms of protein molecular size distribution, loaf volume, and rheological properties using SE-HPLC, baking tests and empirical rheological methods, respectively. In the baking tests, both tin pan loaves and free-form loaves were produced. The VG wheat flour blends yielded varying loaf volumes, which could be attributed to differences in protein molecular size distribution and rheological properties. Free-form loaf volume was significantly correlated to the percentage of unextractable polymeric protein (%UPP) and dough strength, whereas tin pan loaf volume was significantly correlated with dough extensibility. While the alveograph test yielded significant correlations to free-form loaf volume, extensograph parameters were significantly correlated to the volume of both loaf types. In conclusion, the extensograph test may be suitable for VG quality control within the cereal and baking industries.