Effects of Extrusion on Phytic Acid Reduction of Hydrothermal and Fermented Wheat Brans

Wheat bran is a rich source of fibers, minerals and vitamins, which can be used as a valuable byproduct in food industries. However, despite the high nutritional value of wheat bran, presence of phytic acid is a concern because this chemical prevents the bioavailability of minerals.

Based on various studies with the aim of phytic acid reduction, effects of extrusion post process on reducing the phytic acid of pretreated wheat bran via hydrothermal and fermental methods were investigated. To prepare extruded samples, rotating, intermeshing twin-screw extruder with 20 kg/h feeder speed, 300 rpm screw speed, 120 °C temperature and 20% moisture was used.

Results showed that the extrusion process decreased phytic acid in raw, fermented and hydrothermal brans at significant levels (p < 0.05). The highest decreases in phytic acid content was observed for the extrusions of fermented (84.84%), hydrothermal (78.3%) and raw (46%) brans. Extrusion process decreased moisture, pH and brightness (L *) and significantly increased ash, crude fiber and redness (a *) of all raw, fermented and hydrothermal bran samples
(p < 0.05).

Results showed that fermented and hydrothermal wheat brans with extrusion post processing might be used in food formulations as rich sources of dietary fibers with less phytic acid, more bioavailability of minerals and longer shelf lives.