Activation of Endogenous Phytase and Degradation of Phytate in Wheat Bran

Wheat bran contains a significant amount of the anti-nutritional factor phytate. This study is the first to explore the effectiveness of activating endogenous phytase and further reducing phytate content through resulting programmed cell death (PCD). Effects of solid-liquid ratio (1:1, 1:2, 1:3, and 1:6), incubation temperature (4, 20, 38, 55, and 70 °C), metal ions (Na⁺, K⁺, Ca²⁺, and Mg²⁺), gibberellin concentration (0, 5, 50, 500, 2000, and 5000 mg/L), hydrogen peroxide concentration (0, 0.2, 0.4, 0.6, 0.8, and 1.0%), and incubation time (30, 80, 180, and 360 min) on activation of endogenous phytase activity and phytate degradation in wheat bran samples are discussed in this study. It was found that when the wheat bran was incubated with distilled water at 55 °C for 80 min, its endogenous phytase activity was dramatically increased 4-fold from 12.96 to 53.54 FTU/g, whereas the phytate content was reduced by about 70% from 45.20 to 13.52 mg/g. By comparison of photomicrographs of raw wheat bran sample and sample incubated with distilled water for 360 min at 55 °C, a conclusion could be drawn that PCD in aleurone cells had occurred.