Authors: Keqin Ou Yongqiang Cheng Ying Xing Li Lin Robert Nout Jianfen Liang
Publish Date: 2010/11/05
Volume: 48, Issue: 5, Pages: 598-603
Abstract
Phytase in brown rice will be activated and accumulated during seed germination Changes of phytase activity in brown rice during two stages of germination steeping and sprouting affected by process conditions were studied It was shown that steeping led to significant decrease of phytase activity p 001 varying with steeping temperature and steeping medium composition Steeping respectively in demineralized water 05 mM CaCl2 and 01 M H2O2 at 20 °C for 24 h led to the lowest phytase activity in brown rice which was only 25 of that in raw rice At steeping stage steeping media had no significant effect During the sprouting stage phytase activity increased with prolonged time and gradually reached stable levels and with higher temperature in the range of 15–25 °C Phytase activity in brown rice reached 320–340 U kg−1 after 5 d sprouting The evolution pattern of phytase activity during sprouting differed with the solutes previously used during steeping Steeping either with CaCl2 or H2O2 caused a delay followed by a rapid activation of phytase while for control a gradual accumulation of phytase activity was observed Compared with acidic and alkaline steeping solutions demineralized water at neutral 68 pH provided the best pretreatment prior to sprouting at 25 °C to activate maximum levels of phytase Extreme conditions either strong acidic or alkaline inhibited activation of phytase and changed appearance of brown rice kernel as well
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