Bioactive compounds, nutrients and pasting properties of parboiled milled rice, brown rice and germinated brown rice of selected cultivars and the effects of germination durations

Abstract

Germinated brown rice (GBR) was produced from FARO 44, FARO 57 and NERICA-8 cultivars by dehusking the paddies and germinating them at 35 °C for 12, 24 and 36 h. Bioactive compounds, nutritional composition and pasting properties were analysed and compared to that of non-germinated parboiled milled rice (NMR) and non-germinated brown rice (NBR) from the same cultivars. Results showed that germination decreased the pasting properties except breakdown viscosity. It also increased the bioactive compounds and nutrients except total carbohydrate, total starch and amylose contents which were lower in GBR samples. Gamma amino butyric acid (1.85–2.57 mg/100 g), total antioxidant activity (1.25–1.93 µg/100 g), total dietary fibre (8.10–8.25%), protein (10.99–11.05%), lysine (4.16–4.35%), ash (1.32–1.38%), calcium (103.00–120.00 mg/100 g), zinc (1.68–1.89 mg/100 g), vitamin E (1.17–1.42 mg/100 g) of NBR increased in GBR by 92.97–292.97%, 137.6–3689.91%, 6.30–12.85%, 5.19–26.38%, 10.02–12.65%, 46.62–188.41%, 9.42–366.67%, 3.57–43.92% and 21.01–145.30% respectively. Milling reduced each of these parameters significantly (p>0.05). These results differed significantly (p>0.05) amongst the various rice cultivars and germination time. Germination duration of 36 h was optimum for most of the bioactive compounds and nutrients. Germinated form of FARO 57 possessed better bioactive compounds and nutrients than FARO 44 and NERICA-8 cultivars.