Assessment of rheological and microstructural changes of soluble fiber from chia seeds during an in vitro micro-digestion

The ability of some dietary fiber to increase the viscosity of digestive content may be associated with important positive implications in human health. An in vitro micro-digestion device was implemented to simulate and visualize the digestion of mucilage from chia seed. Changes in microstructure in situ and apparent viscosity were evaluated in 3, 5 and 8 g/kg concentrations of mucilage in three different digestions. The mucilage had a high-water holding capacity, approximately 35.2 ± 1.1 g water/g mucilage. As the digestion processes progressed, the microstructure of the digesta changed from a compact sponge-like structure, with small pores forming an irregular network with average pore size of 20.68 ± 6.51; 40.90 ± 7.45 and 15.50 ± 6.07 μm to 3, 5 and 8 g/kg concentrations respectively, to a slightly less compact with average pore size that varies from 19.87 ± 7.00 μm in digestion 1 to 29.79 ± 15.47 μm in digestion 3. A slight reduction in viscosity during the digestion process was observed; this behavior suggests that mucilage could maintain its structure in a food matrix and could be used to develop structured foods. Mucilage from chia seeds could be a potential functional ingredient with valuable attributes for food and nutraceutical industries.