Effect of sprouting on rheological properties of soy-butter

- Soy butter was made from sprouted and unsprouted soybeans.
- Rheograms showed that soybutter was non-Newtonian viscoelastic shear thinning material.
- Shear stress-shear rate relationship was fitted by Ostwald de Waelle model.
- Model parameter values were lower at higher product temperature (10, 25 and 45 °C).
- Sprouting as a pre-treatment affected particle size and rheology of the soy butter.

Sprouted and unsprouted soybeans were roasted and used to prepare soy-butter. Flow properties of these butters were compared with commercially available soy-butter at 10, 25 and 40 °C. Soy-butters behaved like visco-elastic shear thinning material with presence of hysteresis. Their apparent viscosity was significantly affected by shear rate ramping, temperature and sprouting. Ostwald de Waelle model could explain the relationship between shear stress and shear rate. Consistency coefficient, flow behavior index and quantum of hysteresis decreased with increase in product temperature. Butter from sprouted beans showed decreased particle size, apparent viscosity and flow behavior index and increased consistency coefficient compared to butter from unsprouted beans. Results could be useful in improvement of the soy-butter making process, packaging system design and flow behavior prediction during storage.