Impact of grain germination on in vitro antioxidative properties, nutrients digestibility, and functional attributes of brown rice flour

Abstract

AbstractBrown rice was germinated for different times (12, 24, 36, and 48 h) at different temperatures (25, 30, and 35 °C) with the aim to improve the in vitro digestibility and antioxidant potential of the flour made from it. Results showed that increase in germination time and temperature increased in vitro digestibility of starch and protein during germination of brown rice owing to depolymerisation of starch and protein molecules by enzymatic activity. After germination under varying conditions, antioxidant activity increased from 50.19 to 95.58%, total phenolic and flavonoid contents from 0.88 to 2.02 mg GAE/g and 34.06–62.94 mg QE/100g, respectively. Germination at elevated temperature (35 °C) for prolonged time (48 h) also increased the reducing power by 60.49% and metal chelating activity by 114.50% as a result of structural breakdown of bound phenolics. Increased activity of hydrolytic enzymes with progress in the germination time and temperature also results in continuous reduction in the pasting properties and lightness values (L), while increasing a* and b* values of the flour of germinated brown rice. Tailored germination, therefore, can be offered as a tool to increase nutrient digestibility and bioactive potential of brown rice as compared to non-germinated brown rice, thus, producing naturally modified flour with enhanced functionality.