Effect of three modification methods on physical and functional properties of flaxseed cake dietary fiber

Flaxseed cake dietary fiber (FCDF) is an important by-product of the oil manufacturing industry,
but the low bioactivity limits its application. To improve the physical and functional properties of
FCDF, it was separately treated using acidic (AC), cellulase (CE), and acrylate-grafting (AG)
methods. Compared with the untreated FCDF, FCDF modified by AC (FCDF-AC), CE (FCDF-
CE), and AG (FCDF-AG) had looser surface structures and greater flow characteristics. The
hydration capacities were higher for FCDF-AC and FCDF-AG than for FCDF-CE. After
modifications, FCDF showed high adsorption capacities to lipids, cholesterol, and nitrite ions.
Moreover, the hypoglycemic properties of FCDF-CE and FCDF-AG, including glucose
absorption capacity (GAC), glucose dialysis retardation index (GDRI), and α-amylase inhibition
activity (AIA), were higher than those of untreated FCDF. In contrast, the GAC, GDRI, and AIA
were not significantly different between FCDF-AC and FCDF (p > 0.05). Therefore, these results
suggest that modified FCDF can be used as an additive in hypolipidemic and hypoglycemic
foods.