Phytase Assay Kit

Oat and barley bran are high in dietary fiber (β-glucans), minerals, and antioxidants, have high activity of enzymes, but possess also antinutrients. This study aimed to investigate the influence of high-intensity ultrasound on enzyme and antioxidant activities, phytic acid content, as well as functional and rheological properties of oat and barley bran. Ultrasonic treatment was performed at 24 kHz on a 15% bran water suspension, at three specific energies (87, 217.5, and 348 kJ/kg), with or without pulsation (5 sec every 10 sec). Bran was assessed for β-glucanase and phytase activity, phytic acid and total phenolic content, antioxidant activity, hydration, and rheological properties. β-glucanase from oat bran was inactivated up to 82% and from barley bran up to 55%, in dependence of ultrasound specific energy and pulsation. In both bran types, phytase activity increased by 40-44% after treatments with 87 kJ/kg but decreased by 89-94% at 348 kJ/kg. Phytic acid was reduced on average in oat bran by 17% and in barley bran by 39%. Depending on the energy and pulsation, the ultrasonication of both bran types reduced total phenolic content (27-55%), antioxidant activity (by 28-48%), complex viscosity (62-71%) and maximum stress tolerated by the sample (46-68%). In contrast, water swelling (42-48%) and water retention capacity (44–59%) increased for both bran types. Hence, high-intensity ultrasound is a useful technique in reducing antinutrients, while altering the enzyme activity and functional properties of the bran. These results could help wider application of bran in food production.