Effect of high shear mixing on the physicochemical characteristics and functional properties of wheat and oat fibers

Plant-based dietary fibers from cereals such as wheat and oats are increasingly incorporated into food formulations due to their nutritional and health-promoting benefits. However, their native structural characteristics, including high crystallinity, limited surface area, and restricted hydration capacity, can constrain their functionality in complex food systems. This study aimed to investigate the potential of high shear mixing (HSM) as a physical modification strategy to improve the structural and functional properties of wheat, oat-1, and oat-2 fibers. The fibers were subjected to HSM treatment and freeze-dried, and their water-holding capacity (WHC), oil-holding capacity (OHC), swelling behavior, glucose adsorption capacity (GAC), and emulsifying activity were evaluated. Structural alterations were examined using BET surface area analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. HSM combined with freeze-drying markedly modified fiber structure, as reflected in wheat, where the specific surface area increased from 1.30 to 5.62 m 2 /g, porosity rose from 94.59 to 97.56 %, and crystallinity index decreased from 49.88 to 47.75 %. These modifications were accompanied by improved WHC (5.5 to 8.29 g/g) and OHC (5.18 to 9.58 g/g). In contrast, GAC and emulsifying activity of wheat fibers decreased (7.2 to 5.9 mmol/g and 47 % to 45 %, respectively). Oat fibers, particularly oat-2, largely maintained their GAC and emulsifying properties, likely due to their higher soluble fiber fraction, including β-glucans. Overall, HSM demonstrated fiber-specific effects, enhancing hydration- and lipid-binding capacities while reducing some adsorption and interfacial properties. These findings highlight HSM as a promising technique to tailor cereal fibers for targeted food applications. • High shear mixing with freeze drying improved structure and hydration of fibers. • Structural changes confirmed via SEM, XRD, FTIR, and BET analyses. • HSM increased WHC and OHC but reduced GAC and EA in wheat fibers. • The effectiveness of HSM was dependent on the fiber's intrinsic structure. • HSM shows potential for tailoring fibers in sustainable food applications.