Instant White Rice with Pigmented Giant Embryonic Rice Improves Glucose Metabolism and Inhibits Oxidative Stress in High-Fat Diet-Fed Mice

The effects of instant cooked rice made from a combination of white rice and pigmented giant embryonic Keunnunjami rice, in comparison with those of instant regular white or brown rice and instant non-pigmented giant embryonic brown rice, on the glucose metabolism and antioxidant defense status in high-fat diet-fed mice were investigated. 56 male C57BL/6N mice were randomly divided into 7 dietary groups: normal control, high fat (23 %, HF), and HF supplemented with normal white (HF + NW) or brown rice (HF + NB), non-pigmented giant embryonic rice (HF + GB), and white rice with 8 % Keunnunjami (HF + KJ8) and 18 % Keunnunjami (HF + KJ18). After 7 weeks, HF mice showed marked increases in blood glucose (156 mg/dL), plasma insulin (12.1 mg/mL), and lipid peroxidation, and a significant decrease in hepatic glycogen (14.2 mg/g) relative to the control group (p < 0.05). However, addition of instant NB, GB, KJ8, andKJ18) rice suppressed this high-fat diet-induced hyperglycemia and oxidative stress through altering glucose-regulating enzymes (glucokinase, glucose-6-phosphatase, and phosphoenolpyruvate carboxykinase) and activation of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase, glutathione reductase, and paraoxonase). Compared with HF mice, HF + KJ8 and HF + KJ18 groups exhibited significantly lower glucose (139–141 mg/dL), insulin (10.6–10.9 mg/mL), and lipid peroxidation and higher glycogen (15.3–16.4 mg/g) (p < 0.05). The hypoglycemic and antioxidant effects of instant KJ8 and KJ18 rice were generally comparable to those of instant NB and GB rice. These findings illustrate that instant rice made from white rice with 8 % Keunnunjami rice may be useful as a functional food with therapeutic potential against hyperglycemia and oxidative damage.