Effect of parboiling on phytochemical content, antioxidant activity and physicochemical properties of germinated red rice

In order to improve functional properties and palatability of germinated red rice, this study investigated differences in phytochemicals and physicochemical properties of germinated red rice at 2, 5, 10, 15 min of parboiling. Total free phenolic content and antioxidant activity of germinated red rice parboiled for 5 and 15 min was higher than that of germinated red rice. Free p-coumaric acid increased from 0.20 to 0.67 mg/100 g with parboiling time increasing from 5 to 15 min. Bound vanillic (0.17-0.27 mg/100 g) and p-coumaric acid (6.56-8.59 mg/100 g) had higher levels at 0, 2, or 5 min. During 15 min of parboiling, color difference (ΔE) increased from 0.58 to 9.09, heat enthalpy (ΔH) decreased from 4.69 to 1.94 J/g, and internal structure of rice was destroyed. Overall, parboiling time of less than 5 min was suitable to improve the quality of germinated red rice.