Release of mixed linkage (1-->3),(1-->4) beta-D-glucans from barley by protease activity and effects on ileal effluent.

The behaviour of barley beta-glucans in the upper gut has been assessed using ileal effluents recovered from a barley-based test meal. Results have been compared to in vitro treatments used to extract beta-glucans. In vitro, exposure to endogenous proteases led to a solubilisation of beta-glucan, ranging from 28% in the untreated to 83% following NSP isolation. In ileal effluent 60% of the beta-glucan was solubilised, similar to the in vitro treatment. However, the viscosity of the ileal effluent was low, comparable to a mucin standard. Although beta-glucan can be solubilised in the upper gut its viscosity would appear to have only a limited potential to affect nutrient bioavailability.