ABSTRACT
β-Glucan shows great potential for incorporation into bread due to its cholesterol lowering and blood glucose regulating effects, which are related to its viscosity. The effects of β-glucan concentration, gluten addition, premixing, yeast addition, fermentation time, and inactivation of the flour enzymes on the viscosity of extractable β-glucan following incorporation into a white bread dough were studied under physiological conditions, as well as, β-glucan solubility in fermented and unfermented dough. β-Glucan was extracted using an in vitro protocol designed to approximate human digestion and hot water extraction. The viscosity of extractable β-glucan was not affected by gluten addition, the presence of yeast, or premixing. Fermentation produced lower (P ≤ 0.05) extract viscosity for the doughs with added β-glucan, while inactivating the flour enzymes and increasing β-glucan concentration in the absence of fermentation increased (P ≤ 0.05) viscosity. The physiological solubility of the β-glucan concentrate (18.1%) and the β-glucan in the unfermented dough (20.5%) were similar (P > 0.05), while fermentation substantially decreased (P ≤ 0.05) solubility to 8.7%, indicating that the reduction in viscosity due to fermentation may be highly dependent on solubility in addition to β-glucan degradation. The results emphasize the importance of analyzing β-glucan fortified foods under physiological conditions to identify the conditions in the dough system that decrease β-glucan viscosity so that products with maximum functionality can be developed.
