Improving nutritional values in purple rice through germination and parboiling processes

Abstract

© 2020 Wiley Periodicals LLC. The objective of this study was to determine the effects of seed germination and the parboiling process at different temperatures and times on total anthocyanin concentration, antioxidant activity, γ-aminobutyric acid (GABA), and the concentration levels of zinc (Zn) and iron (Fe) in the purple rice variety CMU 107. Germinated parboiled rice (GPR) and non-germinated parboiled rice (NPR) samples were parboiled by being soaked under specific conditions involving a series of temperatures (25°C, 60°C, and 80°C) and times (2, 4, and 6 hr) then being analyzed for the nutritional values. The results showed that the total anthocyanin concentration levels in NPR were about 62.2% higher than those in GPR; however, the antioxidant activity, Zn and GABA concentration levels in GPR were 197.9%, 9.8%, and 5.8% higher than in NPR, respectively. The soaking temperatures and times did not significantly affect the Fe concentrations in all treatments. Practical applications: The process of germination following by parboiling at the appropriate soaking temperature and time could be an effective approach to improve antioxidant capacity, grain Zn, and GABA concentration in purple rice. The successful approach would be applied to use in the individual household and/or scaling up into the industrial units and consequently improve nutritional intake among rice consumers. However, anthocyanin concentration in germinated parboiled grain should be preserved carefully by selecting a specific method.