Rheological differences between wheat and spelt

The usually higher wet gluten content of spelt flours initially suggests good dough properties.

The gluten in spelt differs from the gluten in wheat. In spelt, the gluten, which is crucial for dough formation, consists of glutenin and gliadin, as well. However, spelt lacks some glutenin fractions that are responsible for the greater elasticity of wheat gluten (cf. Longin & Raab 2015). Doughs made from spelt flour are therefore usually more plastic and more unstable than wheat doughs. The differences in the dough rheology of wheat and spelt doughs can be recognised very well in the farinogram and in the extensogram. If you compare the mixing curves (farinograms) of spelt and wheat flours, you can generally recognise a shorter dough development time and poorer dough stability as well as a greater dough softening with spelt as compared to wheat. Furthermore, spelt flours have a slightly lower water absorption than wheat flours. In the extensogram, spelt flours show a lower extensibility resistance and a higher extensibility than wheat doughs. This also results in lower ratio numbers for spelt flours than for wheat flours. The weaker dough properties are partially compensated by increasing the amount of ascorbic acid added during the treatment of spelt flours (4 - 8 mg/100 g flour).

Also when analysed in the alveograph, spelt flours are generally found to have low P values and high L values compared to wheat flours, which suggests that the doughs tend to be less stable and more plastic. The W values and the ratio between P and L are significantly lower than for wheat flour. More detailed explanations regarding the alveograph can be found in chapter „Flour analysis“ under „Alveograph“.