MICRONIZATION OF DE-OILED SUNFLOWER MEAL IMPROVES BIOFUNCTIONAL PROPERTIES

De-oiled sunflower meal is a protein-rich by product of the oil industry, which presents potential for human consumption. The aim of the present study was to evaluate the impact of two drying methods and three particle sizes on the biofunctional properties of sunflower meal rich in protein and fiber. The samples received two drying treatments: (a) tray drying (TD) and freeze-drying (LY); and has been ground into three particle sizes (b) 0.5 mm, 0.3 mm, and 0.45 µm. The content of soluble (SDF) and insoluble (IDF) dietary fiber was assessed using an enzymatic-gravimetric method. SDF content was affected by the thermal treatment and particle size, having a higher value in smaller particles (p<0.05). Additionally, the freeze-dried samples exhibited higher SDF content compared to tray-dried samples. All the samples had a similar amino acid profile. Hypoglycemic activity measured by alpha-amylase showed a half maximal inhibitory concentration (IC50) of 11 mg and 22 mg for the TD0.3 and LY0.3 samples, respectively. The antioxidant potential measured by ORAC method did not show differences (TD0.5: 5.89±0.3; TD0.3: 4.80±0.6; TD0.45: 5.58±0.6; LY0.5: 3.75±1.3; LY0.3: 5.63±1.4; LY0.45: 5.34±0.11 µM TE/g), indicating a similar capacity to neutralize free radicals and protect against oxidative stress within the evaluated parameters, even at a low sample concentration (0.07 mg). In conclusion, drying treatments and particle size had an impact on the solubilization of dietary fibers and hypoglycemic activity, but were similar regarding the amino acid profile and antioxidant properties.