Effect of cell wall degrading enzyme treatment on the phenolic content and antioxidant activity of brown rice

Enzymatic treatments of brown rice flour (BRF) using commercial cell wall degrading enzymes (Celluclast 1.5 L, Pectinex Ultra SP-L) to enhance the phenolic acid content and antioxidant property were investigated. The phenolic acid composition and content were changed substantially by a treatment with commercial cell wall degrading enzymes. These enzymes increased the sum of free phenolic acids by 8.4∼11.2 times, especially for ferulic and p-coumaric acid. Celluclast 1.5 L appeared to be more effective in increasing the total phenolic content than Pectinex Ultra SP-L. The GABA content of BRF with the Celluclast 1.5 L treatment was approximately 43 times higher than that of the control (32.7 vs. 0.76 mg/100 g sample). The ABTS radical scavenging activities of the enzyme treated samples were significantly higher than those of the control. In particular, the Celluclast 1.5 L treated sample was approximately 2.5 times higher than that of the control sample. Enzymatic hydrolysis of the cell wall polysaccharides in BRF could be used as an effective procedure for increasing not only the phenolic acid and GABA content, but also the antioxidant activity.