Effect of Germination on the Antioxidant Capacity of Pigmented Rice (<i>Oryza sativa</i> L. cv. Superjami and Superhongmi)

Abstract

The effect of germination on the antioxidant capacity of pigmented and non-pigmented rice was investigated.The blackish purple Superjami, reddish-brown Superhongmi, and ordinary non-pigmented brown rice were germinated for 72 h. The germinated rice grains were extracted with 80% methanol and their antioxidant activities and compounds were analyzed. Germination substantially increased the free radical scavenging activity, reducing power, ferrous chelating ability, and superoxide dismutase activity in all the rice samples. The anthocyanin, tannin, phenolic, phytic acid, tocopherol, and tocotrienol contents were markedly higher in germinated rice compared to those of the non-germinated ones. The pigmented varieties exhibited greater antioxidant capacity and higher amounts of antioxidant compounds than the non-pigmented brown rice in both germinated and non-germinated forms. Superjami showed higher antioxidant activities and anthocyanin, phenolic, tocopherol, and tocotrienol contents than Superhongmi. These findings illustrate that germination could increase the antioxidant compounds and enhance the antioxidant capacity of pigmented rice which may be useful as functional foods.Keywords: pigmented rice, germination, antioxidant activity, antioxidant compounds IntroductionGermination has been shown to improve the nutritional value and increase the amount of bioactive compounds in various cereal grains including rice, oat, wheat, and barley (Hubner and Arendt, 2013). It has also been reported that germination could improve the texture and eating quality of brown rice (Wu et al., 2013b). This process involves soaking of the grains in water for a few days to induce slight germination. The rice is considered germinated when the primary root is already visible (Moongngarm and Khomphiphatkul, 2011). A number of studies have shown that germinated rice possesses various pharmacological properties, such antidiabetic, antihyperlipidemia, antioxidant, and anticancer (Mohd Esa et al., 2013;Patil and Khan, 2011;Wu et al., 2013b).Biochemical changes occur during germination of rice which causes softening of the endosperm and an increase in nutrient bioavailability (Islam and Becerra, 2012;Patil and Khan, 2011).Pigmented rice varieties are rice grains with colored pericarp and have been shown to have higher amounts of nutrients and greater antioxidant capacity than ordinary non-pigmented rice (Laokdiluk et al., 2011;Kang et al., 2013). A study conducted by Nam et al. (2005) revealed that extracts from pigmented rice brans have anticancer and antimutagenic properties. Moreover, consumption of pigmented rice has been associated with reduced risk of developing hyperlipidemia and cardiovascular disease (Ling et al., 2001). Due to the high antioxidant potential and functional properties of pigmented rice, new lines of this variety with enhanced biofunctional properties are continuously being developed and produced. In Korea, new pigmented rice varieties, Superjami and Superhongmi, have been recently developed through conventional breedin...

Germinated Pigmented Rice (Oryza Sativa L. cv. Superhongmi) Improves Glucose and Bone Metabolisms in Ovariectomized Rats

“…Between the two Superhongmi rice-fed groups, the GSH rats exhibited a greater body weight-lowering effect and hypoglycemic activity than the SH group. Germinated rice, especially pigmented cultivar, contains substantially higher amounts of bioactive compounds than non-germinated rice [4,5,19]. In the present study, γ-oryzanol, GABA, phytic acid, tocols, and policosanol were significantly higher in a germinated rice sample than that of the non-germinated one.…”

“…Rice cultivars with colored pericarp, such as Superhongmi, are rich in antioxidant compounds such as anthocyanins, tocols, γ-oryzanol, and phytic acid [53] and germination could further increase the amount of these antioxidant compounds. Germinated Superhongmi rice has been previously reported to contain a substantial amount of antioxidant compounds and to have a strong antioxidant capacity [19]. Past investigations revealed that dietary antioxidants could prevent bone loss in postmenopausal women and ovariectomized animals and may be useful in the prevention and treatment of osteoporosis [54,55].…”

“…Recent studies have shown that germinated Superhongmi rice has a strong antioxidant capacity and could improve the lipid metabolism in ovariectomized rats [19,20]. To further explore the therapeutic potential of Superhongmi rice against metabolic dysfunctions, particularly those caused by menopause, the present study investigated the effect of germinated Superhongmi rice on the glucose metabolism and bone turnover in the postmenopausal-like model of ovariectomized rats.…”

Effect of Germinated Pigmented Rice “Superjami” on the Glucose Level, Antioxidant Defense System, and Bone Metabolism in Menopausal Rat Model

“…GR enzyme transforms oxidized glutathione into reduced glutathione, an antioxidant [43], while PON enzyme reduces lipid peroxides and hydrolyzes oxidized phospholipids [44]. Superjami rice is rich in natural antioxidants, and germination further increases the amount of these antioxidant compounds, which may have been responsible for the enhanced antioxidant defense status in OVX rats [15]. Studies have shown that Superjami rice inhibited oxidative stress and enhanced the antioxidant enzyme activities in high fat-fed mice and that its antioxidant capacity markedly increased after germination [1,15].…”

“…Moreover, dormancy enzymes are activated during rice germination, resulting in the degradation of large biomolecules and the production of bioactive substances [14]. Germination has been found to increase the quantity of antioxidant compounds and enhance the antioxidant capacity of Superjami rice [15]. Further, dietary supplementation of germinated Superjami rice has been previously shown to ameliorate the lipid metabolism and reduce the risk of dyslipidemia in menopause animal model [16].…”