Physicochemical Properties and Bioactive Compounds of Pigmented Red Rice Affected by Soaking and Germination

Abstract

This study investigates the physicochemical properties and bioactive compounds of red pigmented rice (colored rice) by examining soaking and germination rates. As evaluated from the germination rate and sprout length of the germinating red rice, the optimal soaking condition was determined to be approximately 24 hours of soaking before germination. Increased germination time resulted in an increase in the L*and b*values and decreased a*value. Crude protein, crude fat, and crude ash contents in red rice were increased during germination, whereas the starch content was decreased. The α-amylase activity of red rice was higher than ordinary brown rice and showed rapid increase after 72 hours of germination, but β-amylase activity increased only slightly. The amounts of bioactive compounds, including γ-aminobutyric acid, total phenolics, and flavonoids in red rice, were increased during germination and were higher than values obtained in germinating ordinary brown rice.