Evaluation of rheological, physicochemical, thermal, mechanical and sensory properties of oat-based gluten free cookies

• β-Glucan content increased by 89% in the oat bran cookie compared with oat flour.
• Bran affects water absorption, protein weakening, stability of gelatinized starch.
• Gelatinization degree of oat gluten-free cookies increased with oat bran addition.
• E-nose provided a discrimination index of 87 between oat flour and oat bran cookies.
• SEM indicated differences in the internal structure of the cookies.

Oat bran (OB) is a high fibre source with human health benefits. Gluten-free cookies were prepared by incorporation of OB (0%, 30%, 50%, 70% and 100%) into oat flour (OF).Dough rheology for OF/OB mixtures indicated no change in starch gelatinization and retrogradation between 30% and 70% OB when compared with OF. OB incorporation increased protein weakening and decreased the stability of gelatinized starch. Cookies were evaluated based on thermal properties and the enthalpy decreased by 60%. SEM revealed differences in internal structure of the cookies and e-nose technique provided a good discrimination of cookies based on the overall flavour. The highest β-glucan content (4.37% dm) was achieved in the 100% OB cookies with an overall acceptability of 5.6. Incorporation of OB provided darker samples and cookies become more brittle (hardness was reduced to 18.33 N).Results showed that OB can be used to enhance the nutritional properties of gluten-free oat cookies.